Southwest Airlines (LUV) 10-K 6 Feb 15 2014 FY Annual report Financial data

Document_And_Entity_Informatio

Document And Entity Information (USD $)	12 Months Ended
	Dec. 31, 2014	Feb. 04, 2015	Jun. 30, 2014
Document And Entity Information [Abstract]
Entity Registrant Name	SOUTHWEST AIRLINES CO
Entity Central Index Key	92380
Current Fiscal Year End Date	-19
Entity Filer Category	Large Accelerated Filer
Document Type	10-K
Document Period End Date	31-Dec-14
Document Fiscal Year Focus	2014
Document Fiscal Period Focus	FY
Amendment Flag	FALSE
Entity Common Stock, Shares Outstanding		675,993,892
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float			$18,358,439,198

Consolidated_Balance_Sheet

Consolidated Balance Sheet (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Current assets:
Cash and cash equivalents	$1,282	$1,355
Short-term investments	1,706	1,797
Accounts and other receivables	365	419
Inventories of parts and supplies, at cost	342	467
Deferred income taxes	477	168
Prepaid expenses and other current assets	232	250
Total current assets	4,404	4,456
Property and equipment, at cost:
Flight equipment	18,473	16,937
Ground property and equipment	2,853	2,666
Deposits on flight equipment purchase contracts	566	764
Assets constructed for others	621	453
Property and equipment, at cost	22,513	20,820
Less allowance for depreciation and amortization	8,221	7,431
Property and equipment, net	14,292	13,389
Goodwill	970	970
Other assets	534	530
Total assets	20,200	19,345
Current liabilities:
Accounts payable	1,203	1,247
Accrued liabilities	1,565	1,229
Air traffic liability	2,897	2,571
Current maturities of long-term debt	258	629
Total current liabilities	5,923	5,676
Long-term debt less current maturities	2,434	2,191
Deferred income taxes	3,259	2,934
Construction obligation	554	437
Other noncurrent liabilities	1,255	771
Stockholders' equity:
Common stock, $1.00 par value: 2,000,000,000 shares authorized; 807,611,634 shares issued in 2014 and 2013	808	808
Capital in excess of par value	1,315	1,231
Retained earnings	7,416	6,431
Accumulated other comprehensive loss	-738	-3
Treasury stock, at cost: 132,017,550 and 107,136,946 shares in 2014 and 2013 respectively	-2,026	-1,131
Total stockholders' equity	6,775	7,336
Total liabilities and stockholders' equity	$20,200	$19,345

Consolidated_Balance_Sheet_Par

Consolidated Balance Sheet (Parenthetical) (USD $)	Dec. 31, 2014	Dec. 31, 2013
Stockholders' equity:
Common stock, par value (in dollars per share)	$1	$1
Common stock, shares authorized (in shares)	2,000,000,000	2,000,000,000
Common stock, shares issued (in shares)	807,611,634	807,611,634
Treasury stock, at cost: shares (in shares)	132,017,550	107,136,946

Consolidated_Statement_of_Inco

Consolidated Statement of Income (USD $)	12 Months Ended
In Millions, except Per Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
OPERATING REVENUES:
Passenger	$17,658	$16,721	$16,093
Freight	175	164	160
Other	772	814	835
Total operating revenues	18,605	17,699	17,088
OPERATING EXPENSES:
Salaries, wages, and benefits	5,434	5,035	4,749
Fuel and oil	5,293	5,763	6,120
Maintenance materials and repairs	978	1,080	1,132
Aircraft rentals	295	361	355
Landing fees and other rentals	1,111	1,103	1,043
Depreciation and amortization	938	867	844
Acquisition and integration	126	86	183
Other operating expenses	2,205	2,126	2,039
Total operating expenses	16,380	16,421	16,465
OPERATING INCOME	2,225	1,278	623
OTHER EXPENSES (INCOME):
Interest expense	130	131	147
Interest Costs Capitalized Adjustment	-23	-24	-21
Interest income	-7	-6	-7
Other (gains) losses, net	309	-32	-181
Total other expenses (income)	409	69	-62
INCOME BEFORE INCOME TAXES	1,816	1,209	685
PROVISION FOR INCOME TAXES	680	455	264
NET INCOME	$1,136	$754	$421
NET INCOME PER SHARE, BASIC (in dollars per share)	$1.65	$1.06	$0.56
NET INCOME PER SHARE, DILUTED (in dollars per share)	$1.64	$1.05	$0.56
Cash dividends declared per common share (in dollars per share)	$0.22	$0.13	$0.03

Consolidated_Statement_of_Comp

Consolidated Statement of Comprehensive Income (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Net income	$1,136	$754	$421
Unrealized gain (loss) on defined benefit plan items, net of deferred taxes of ($8), $15, and ($11)	-16	24	-17
Other, net of deferred taxes of $0, $7, and $3	0	9	3
OTHER COMPREHENSIVE INCOME (LOSS)	-735	116	105
COMPREHENSIVE INCOME	401	870	526
Fuel derivatives
Unrealized gain (loss) on derivatives, net of tax	-727	52	120
Interest rate derivatives
Unrealized gain (loss) on derivatives, net of tax	$8	$31	($1)

Consolidated_Statement_of_Comp1

Consolidated Statement of Comprehensive Income (Parenthetical) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Deferred taxes on unrealized gain (loss), other, tax effect	$0	$7	$3
Deferred taxes on postretirement	8	15	-11
Fuel derivatives
Deferred taxes on unrealized gain (loss) on derivatives, tax effect	-430	31	74
Interest rate derivatives
Deferred taxes on unrealized gain (loss) on derivatives, tax effect	$5	$19	$0

Consolidated_Statement_of_Stoc

Consolidated Statement of Stockholder's Equity (USD $)	Total	Common Stock	Capital in excess of par value	Retained earnings	Accumulated other comprehensive income (loss)	Treasury stock
In Millions, unless otherwise specified
Balance at beginning of period at Dec. 31, 2011	$6,877	$808	$1,222	$5,395	($224)	($324)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Repurchase of common stock	-400	0	0	0	0	-400
Issuance of common and treasury stock pursuant to Employee stock plans	23	0	-4	-22	0	49
Net tax benefit (expense) of options exercised	-24	0	-24	0	0	0
Share-based compensation	16	0	16	0	0	0
Cash dividends	-26	0	0	-26	0	0
Comprehensive income	526	0	0	421	105	0
Balance at end of period at Dec. 31, 2012	6,992	808	1,210	5,768	-119	-675
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Repurchase of common stock	-540	0	0	0	0	-540
Issuance of common and treasury stock pursuant to Employee stock plans	96	0	12	0	0	84
Net tax benefit (expense) of options exercised	-9	0	-9	0	0	0
Share-based compensation	18	0	18	0	0	0
Cash dividends	-91	0	0	-91	0	0
Comprehensive income	870	0	0	754	116	0
Balance at end of period at Dec. 31, 2013	7,336	808	1,231	6,431	-3	-1,131
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Repurchase of common stock	-955	0	0	0	0	-955
Issuance of common and treasury stock pursuant to Employee stock plans	100	0	40	0	0	60
Net tax benefit (expense) of options exercised	23	0	23	0	0	0
Share-based compensation	21	0	21	0	0	0
Cash dividends	-151	0	0	-151	0	0
Comprehensive income	401	0	0	1,136	-735	0
Balance at end of period at Dec. 31, 2014	$6,775	$808	$1,315	$7,416	($738)	($2,026)

Consolidated_Statement_of_Stoc1

Consolidated Statement of Stockholder's Equity (Parenthetical) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Statement of Stockholders' Equity [Abstract]
Cash dividends, per share (in dollars per share)	$0.22	$0.13	$0.03

Consolidated_Statement_of_Cash

Consolidated Statement of Cash Flows (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$1,136	$754	$421
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation and amortization	938	867	844
Unrealized (gain) loss on fuel derivative instruments	279	-5	-189
Deferred income taxes	501	50	251
Changes in certain assets and liabilities:
Accounts and other receivables	54	-17	-33
Other assets	142	-46	-104
Accounts payable and accrued liabilities	36	343	186
Air traffic liability	326	400	334
Cash collateral received from (provided to) derivative counterparties	-233	57	233
Other, net	-277	74	121
Net cash provided by operating activities	2,902	2,477	2,064
Net cash used in investing activities
Capital expenditures	-1,748	-1,433	-1,348
Assets constructed for others	-80		0
Prior Period Reclassification Adjustment		14
Purchases of short-term investments	-3,080	-3,135	-2,481
Proceeds from sales of short-term and other investments	3,185	3,198	2,996
Other, net	-4	0	0
Net cash used in investing activities	-1,727	-1,384	-833
Net cash used in financing activities
Proceeds from issuance of long-term debt	300	0	0
Proceeds from Employee stock plans	110	96	27
Reimbursement for assets constructed for others	27	0	0
Proceeds from termination of interest rate derivative instrument	0	0	38
Payments of long-term debt and capital lease obligations	-561	-313	-578
Payments of cash dividends	-139	-71	-22
Repayment of construction obligation	-11	-5	0
Repurchase of common stock	-955	-540	-400
Other, net	-19	-18	-12
Net cash used in financing activities	-1,248	-851	-947
NET CHANGE IN CASH AND CASH EQUIVALENTS	-73	242	284
CASH AND CASH EQUIVALENTS AT BEGINNING OF PERIOD	1,355	1,113	829
CASH AND CASH EQUIVALENTS AT END OF PERIOD	1,282	1,355	1,113
CASH PAYMENTS FOR:
Interest	128	133	153
Income taxes	155	346	100
SUPPLEMENTAL DISCLOSURE OF NONCASH TRANSACTIONS:
Assets constructed for others	$88	$105	$129

SUMMARY_OF_SIGNIFICANT_ACCOUNT

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
	Basis of Presentation
	Southwest Airlines Co. (the “Company”) operates Southwest Airlines, a major domestic airline. The Consolidated Financial Statements include the accounts of the Company and its wholly owned subsidiaries, which include AirTran Holdings, LLC. On May 2, 2011 (the “acquisition date”), the Company acquired all of the outstanding equity of AirTran Holdings, Inc. (“AirTran Holdings”), the former parent company of AirTran Airways, Inc. (“AirTran Airways”). Throughout these Notes, the Company makes reference to AirTran, which is meant to be inclusive of the following: (i) for periods prior to the acquisition date, AirTran Holdings and its subsidiaries, including, among others, AirTran Airways; and (ii) for periods on and after the acquisition date, AirTran Holdings, LLC, the successor to AirTran Holdings, and its subsidiaries, including among others, AirTran Airways. The accompanying Consolidated Financial Statements include the results of operations and cash flows for all periods presented and all significant inter-entity balances and transactions have been eliminated. The preparation of financial statements in conformity with generally accepted accounting principles in the United States (GAAP) requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. Actual results could differ from these estimates.
	Certain prior period amounts have been reclassified to conform to the current presentation. In the Consolidated Statement of Cash Flows for the year ended December 31, 2013, the Company has reclassified $14 million from Capital expenditures to Assets constructed for others. See Note 4 for further information.
	Cash and cash equivalents
	Cash in excess of that necessary for operating requirements is invested in short-term, highly liquid, income-producing investments. Investments with original maturities of three months or less when purchased are classified as cash and cash equivalents, which primarily consist of certificates of deposit, money market funds, and investment grade commercial paper issued by major corporations and financial institutions. Cash and cash equivalents are stated at cost, which approximates fair value.
	As of December 31, 2014, $266 million in cash collateral deposits were provided by the Company to its fuel hedge counterparties and no cash collateral deposits were held by or provided by the Company to its interest rate hedge counterparties. As of December 31, 2013, the Company had no cash collateral deposits held by or provided by the Company to its fuel hedge counterparties and the Company had provided cash collateral deposits totaling $32 million to its interest rate hedge counterparties. Cash collateral amounts provided or held associated with fuel and interest rate derivative instruments are not restricted in any way and earn interest income at an agreed upon rate that approximates the rates earned on short-term securities issued by the U.S. Government. Depending on the fair value of the Company’s fuel and interest rate derivative instruments, the amounts of collateral deposits held or provided at any point in time can fluctuate significantly. See Note 10 for further information on these collateral deposits and fuel derivative instruments.
	Short-term and noncurrent investments
	Short-term investments consist of investments with original maturities of greater than three months but less than twelve months when purchased. These are primarily short-term securities issued by the U.S. Government and certificates of deposit issued by domestic banks. All of these investments are classified as available-for-sale securities and are stated at fair value, which approximates cost. For all short-term investments, at each reset period or upon reinvestment, the Company accounts for the transaction as Proceeds from sales of short-term investments for the security relinquished, and Purchases of short-investments for the security purchased, in the accompanying Consolidated Statement of Cash Flows. Unrealized gains and losses, net of tax, if any, are recognized in Accumulated other comprehensive income (loss) (“AOCI”) in the accompanying Consolidated Balance Sheet. Realized net gains and losses on specific investments, if any, are reflected in Interest income in the accompanying Consolidated Statement of Income. Both unrealized and realized gains and/or losses associated with investments were immaterial for all years presented.
	Noncurrent investments consist of investments with maturities of greater than twelve months. At December 31, 2014, these primarily consisted of the Company’s auction rate security instruments that it expects will not be redeemed during 2015. See Note 11 for further information. Noncurrent investments are included as a component of Other assets in the Consolidated Balance Sheet.
	Accounts and other receivables
	Accounts and other receivables are carried at cost. They primarily consist of amounts due from credit card companies associated with sales of tickets for future travel, amounts due from business partners in the Company’s frequent flyer program, and amounts due from counterparties associated with fuel derivative instruments that have settled. The allowance for doubtful accounts was immaterial at December 31, 2014 and 2013. In addition, the provision for doubtful accounts and write-offs for 2014 and 2013 were each immaterial.
	Inventories
	Inventories consist primarily of aircraft fuel, flight equipment expendable parts, materials, and supplies. All of these items are carried at average cost, less an allowance for obsolescence. These items are generally charged to expense when issued for use. The reserve for obsolescence was $46 million and $36 million at December 31, 2014, and 2013, respectively. In addition, the Company’s provision for obsolescence and write-offs for 2014, 2013, and 2012 were each immaterial.
	Property and equipment
	Property and equipment is stated at cost. Capital expenditures includes payments made for aircraft, other flight equipment, purchase deposits related to future aircraft deliveries, and ground and other property and equipment. Depreciation is provided by the straight-line method to estimated residual values over periods generally ranging from 23 to 25 years for flight equipment and 5 to 30 years for ground property and equipment once the asset is placed in service. Residual values estimated for aircraft generally range from 2 to 20 percent and for ground property and equipment generally range from 0 to 10 percent. Property under capital leases and related obligations are initially recorded at an amount equal to the present value of future minimum lease payments computed on the basis of the Company’s incremental borrowing rate or, when known, the interest rate implicit in the lease. Amortization of property under capital leases is on a straight-line basis over the lease term and is included in Depreciation and amortization expense. Leasehold improvements generally are amortized on a straight-line basis over the shorter of the estimated useful life of the improvement or the remaining term of the lease. Assets constructed for others primarily consists of airport improvement projects, once placed into service, in which the Company is considered the accounting owner of the facilities, and such assets are amortized to estimated residual value over the term of the Company's lease or the expected life of the asset. See Note 4 for further information.
	The Company evaluates its long-lived assets used in operations for impairment when events and circumstances indicate that the undiscounted cash flows to be generated by that asset are less than the carrying amounts of the asset and may not be recoverable. Factors that would indicate potential impairment include, but are not limited to, significant decreases in the market value of the long-lived asset(s), a significant change in the long-lived asset’s physical condition, and operating or cash flow losses associated with the use of the long-lived asset. If an asset is deemed to be impaired, an impairment loss is recorded for the excess of the asset book value in relation to its estimated fair value.
	During first quarter 2012 the Company changed the estimated retirement dates of several 737-300 and 737-500 aircraft based on revisions in the Company’s fleet plan. This change, which was accounted for on a prospective basis, resulted in an acceleration of depreciation expense, since the majority of these aircraft had previously been expected to retire in periods beyond 2012, but were subsequently expected to be retired during 2012. The impact of this change on the year ended December 31, 2012 was an increase to Depreciation expense of $12 million. Excluding the impact of Profitsharing and income taxes, the change resulted a $6 million decrease to Net income and a $0.01 decrease to Basic and Diluted Net income per share for the year ended December 31, 2012.
	During third quarter 2012 the Company changed the estimated residual values of its entire fleet of owned 737-300 and 737-500 aircraft. This change was based on an agreement entered into during July 2012, pursuant to which the Company will lease or sublease certain aircraft to Delta Air Lines, Inc., and the resulting impact this transaction will have on how the Company manages the ultimate retirement of its owned 737-300 and 737-500 aircraft. See Note 7 for further information on the lease/sublease transaction. Based on the expected retirement dates and then current and expected future market conditions related to its owned 737-300 and 737-500 aircraft, the Company reduced the residual values of these aircraft from approximately ten percent of original cost to approximately two percent of original cost. As this reduction in residual value was considered a change in estimate, it was accounted for on a prospective basis, and thus the Company will record additional depreciation expense over the remainder of the useful lives for each aircraft. The impact of this change on the year ended December 31, 2012 was an increase to Depreciation expense of $34 million. Excluding the impact of Profitsharing and income taxes, the change resulted an $18 million decrease to Net income and a $0.02 decrease to Basic and Diluted Net income per share for the year ended December 31, 2012.
	Aircraft and engine maintenance
	The cost of scheduled inspections and repairs and routine maintenance costs for all aircraft and engines are charged to Maintenance materials and repairs expense as incurred. The Company also has “power-by-the-hour” agreements related to certain of its aircraft engines with external service providers. Under these agreements, which the Company has determined effectively transfers the risk and creates an obligation associated with the maintenance on such engines to the counterparty, expense is recorded commensurate with each hour flown on an engine. In situations where the payments to the counterparty do not sufficiently match the level of services received during the period, expense is recorded on a straight-line basis over the term of the agreement based on our best estimate of expected future aircraft utilization. For its engine maintenance contracts that do not transfer risk to the service provider, the Company records expense on a time and materials basis when an engine repair event takes place. Modifications that significantly enhance the operating performance or extend the useful lives of aircraft or engines are capitalized and amortized over the remaining life of the asset.
	Goodwill and intangible assets
	The Company applies a fair value based impairment test to the carrying value of goodwill and indefinite-lived intangible assets on an annual basis (as of October 1), or more frequently if certain events or circumstances indicate that an impairment loss may have been incurred. The FASB standard “Testing Indefinite-Lived Intangible Assets for Impairment” gives companies the option to perform a qualitative assessment to determine whether it is more likely than not that an indefinite-lived intangible asset is impaired rather than calculating the fair value of the indefinite-lived intangible asset. The Company adopted this standard and has applied the provisions to its annual indefinite-lived intangible asset impairment test for 2014.
	The Company first utilizes a qualitative approach and analyzes various factors to determine if events and circumstances have affected the fair value of the goodwill and indefinite-lived intangible assets. If the Company determines it is more likely than not that the asset value may be impaired, the Company then uses the quantitative approach to assess the asset’s fair value and amount of impairment. As a result of the Company’s qualitative analyses performed during 2014 the Company concluded it was more likely than not that the fair values of its Goodwill and Indefinite-lived intangible assets was greater than the carrying value and; therefore, a quantitative assessment was not necessary.
	Intangible assets primarily consist of acquired leasehold rights to certain airport owned gates at Chicago’s Midway International Airport, take-off and landing slots at certain domestic slot-controlled airports, and certain intangible assets recognized from the AirTran acquisition. The following table is a summary of the Company’s intangible assets, which are included as a component of Other assets in the Company's Consolidated Balance Sheet, as of December 31, 2014 and 2013:
			Year ended December 31, 2014				Year ended December 31, 2013
	(in millions)	Weighted-average useful life (in years)	Gross carrying		Accumulated		Gross carrying amount		Accumulated Amortization
			amount		amortization
	Customer relationships/marketing agreements	9	$	38	$	26	$	39	$	23
	Trademarks/trade names	6	36		30		36		25
	Owned domestic slots	Indefinite	303		n/a		93		n/a
	Leased domestic slots (a)	39	19		5		19		4
	Non-compete agreements	2	5		5		5		5
	Gate leasehold rights	19	60		32		60		29
	Total	15	$	461	$	98	$	252	$	86
	(a) Useful life of leased slots is based on the stated lease term.
	During fourth quarter 2013, following the Company’s acquisition of additional slots at New York’s LaGuardia Airport, the Company made the determination that all of its owned domestic slots should be assigned an indefinite life and would thus not be subject to further amortization, including those that are owned but leased to other carriers. In addition, during first quarter 2014, the Company acquired additional slots at Washington’s Ronald Reagan National Airport which were also assigned an indefinite life. Among other factors, the determination that all of the Company's owned domestic slots should be assigned an indefinite life was due to the Company’s reassessment of the current size and importance of its operations at New York’s LaGuardia Airport and Washington’s Ronald Reagan National Airport versus when the Company first began service to these airports in recent years. The impact of this prospective change in accounting estimate is immaterial.
	The aggregate amortization expense for 2014, 2013, and 2012 was $13 million, $19 million, and $25 million, respectively. Estimated aggregate amortization expense for the five succeeding years and thereafter is as follows: 2015 – $11 million, 2016 – $8 million, 2017 – $5 million, 2018 – $5 million, 2019 – $4 million, and thereafter – $27 million.
	Revenue recognition
	Tickets sold are initially deferred as Air traffic liability. Passenger revenue is recognized when transportation is provided. Air traffic liability primarily represents tickets sold for future travel dates and estimated refunds and exchanges of tickets sold for past travel dates. The majority of the Company’s tickets sold are nonrefundable. Refundable tickets that are sold but not flown on the travel date can be reused for another flight, up to a year from the date of sale, or refunded. A small percentage of tickets (or partial tickets) expire unused. The Company estimates the amount of tickets that expire unused and recognizes such amounts in Passenger revenue using the redemption method based on scheduled flight date. Prior to September 13, 2013, funds associated with tickets in which a passenger did not show up for a flight without canceling were able to be reused on another flight for up to twelve months. On September 13, 2013, Southwest implemented a No Show policy that applies to nonrefundable fares that are not canceled or changed by a Customer at least ten minutes prior to a flight's scheduled departure. Based on the Company's revenue recognition policy, revenue is now recorded at the flight date for a Customer who does not change his/her itinerary and loses his/her funds. Amounts collected from passengers for ancillary services such as baggage and other fees are generally recognized as Other revenue when the service is provided, which is typically the flight date.
	The Company's policy is to record revenue for the estimated spoilage of tickets (including partial tickets) once the flight date has passed, under the redemption method. Initial spoilage estimates are routinely adjusted and ultimately finalized once the tickets expire, which is typically twelve months after the original purchase date. Spoilage estimates are based on the Customers' historical travel behavior as well as assumptions about the Customers' future travel behavior. Assumptions used to generate spoilage estimates can be impacted by several factors including, but not limited to: fare increases, fare sales, changes to the Company's ticketing policies, changes to the Company’s refund, exchange and unused funds policies, or economic factors.
	The Company is also required to collect certain taxes and fees from Customers on behalf of government agencies and remit these back to the applicable governmental entity on a periodic basis. These taxes and fees include U.S. federal transportation taxes, federal security charges, and airport passenger facility charges. These items are collected from Customers at the time they purchase their tickets, but are not included in Passenger revenue. The Company records a liability upon collection from the Customer and relieves the liability when payments are remitted to the applicable governmental agency.
	Frequent flyer program
	The Company records a liability for the estimated incremental cost of providing free travel under its frequent flyer program for all amounts earned from flight activity that are expected to be redeemed for future travel. The estimated incremental cost includes direct passenger costs such as fuel, food, and other operational costs, but does not include any contribution to fixed overhead costs or profit.
	Southwest also sells frequent flyer points and related services to companies participating in its frequent flyer program. Funds received from the sale of these points are accounted for using the residual method. Under this method, the Company determined the portion of funds received that relate to free travel were currently estimated to be 100 percent of the amount received under the Company's Rapid Reward program as of December 31, 2014. These amounts are deferred and recognized as Passenger revenue when the ultimate free travel awards are flown. For all points sold to business partners that are expected to expire unused, the Company recognizes spoilage in accordance with the redemption method. The Company's consolidated liability associated with the sale of frequent flyer points and/or flight credits, was approximately $1.3 billion and $1.1 billion as of December 31, 2014, and 2013, respectively. This liability is included as part of Air Traffic liability in the Company’s Consolidated Balance Sheet.
	During fourth quarter 2014, the Company increased the amount of spoilage recorded associated with frequent flyer points sold to business partners as a result of continued monitoring of Member redemption activity and behavior under its Rapid Rewards program. Based on a sufficient amount of historical data and Member attributes observed since the new program was launched in 2011, the Company developed a predictive statistical model to analyze the amount of spoilage expected. In estimating spoilage, the Company takes into account the Member’s past behavior, as well as several factors that are expected to be indicative of the likelihood of future point redemption. These factors include, but are not limited to, tenure with program, points accrued in the program, and whether or not the customer has a co-branded credit card. This change in estimate, which was recorded on a prospective basis, effective October 1, 2014, increased Passenger revenues by approximately $55 million for the quarter and the year ended December 31, 2014. After consideration of profitsharing and taxes, the impact of this change to net income was an increase of $29 million, or $.04 per Basic and Diluted share, for the year ended December 31, 2014. The higher spoilage rate is expected to continue in 2015; however, the precise revenue impact will not be determinable until the actual number of point redemptions for the period is known.
	Advertising
	Advertising costs are charged to expense as incurred. Advertising and promotions expense for the years ended December 31, 2014, 2013, and 2012 was $207 million, $208 million, and $223 million, respectively, and is included as a component of Other operating expense in the accompanying Consolidated Statement of Income.
	Share-based Employee compensation
	The Company has share-based compensation plans covering certain Employees, including plans covering the Company’s Board of Directors. The Company accounts for share-based compensation based on its grant date fair value. See Note 9 for further information.
	Financial derivative instruments
	The Company accounts for financial derivative instruments at fair value and applies hedge accounting rules where appropriate. The Company utilizes various derivative instruments, including jet fuel, crude oil, unleaded gasoline, and heating oil-based derivatives, to attempt to reduce the risk of its exposure to jet fuel price increases. These instruments consist primarily of purchased call options, collar structures, call spreads, put spreads, and fixed price swap agreements, and upon proper qualification are accounted for as cash-flow hedges. The Company also has interest rate swap agreements to convert a portion of its fixed-rate debt to floating rates and has swap agreements that convert certain floating-rate debt to a fixed-rate. These interest rate hedges are appropriately designated as either fair value hedges or as cash flow hedges.
	Since the majority of the Company’s financial derivative instruments are not traded on a market exchange, the Company estimates their fair values. Depending on the type of instrument, the values are determined by the use of present value methods or option value models with assumptions about commodity prices based on those observed in underlying markets. Also, since there is not a reliable forward market for jet fuel, the Company must estimate the future prices of jet fuel in order to measure the effectiveness of the hedging instruments in offsetting changes to those prices. Forward jet fuel prices are estimated through utilization of a statistical-based regression equation with data from market forward prices of like commodities. This equation is then adjusted for certain items, such as transportation costs, that are stated in the Company’s fuel purchasing contracts with its vendors.
	For the effective portion of settled fuel hedges, the Company records the associated gains or losses as a component of Fuel and oil expense in the Consolidated Statement of Income. For amounts representing ineffectiveness, as defined, or changes in fair value of derivative instruments for which hedge accounting is not applied, the Company records any gains or losses as a component of Other (gains) losses, net, in the Consolidated Statement of Income. Amounts that are paid or received in connection with the purchase or sale of financial derivative instruments (i.e., premium costs of option contracts) are classified as a component of Other (gains) losses, net, in the Consolidated Statement of Income in the period in which the instrument settles or expires. All cash flows associated with purchasing and selling derivatives are classified as operating cash flows in the Consolidated Statement of Cash Flows, within Changes in certain assets and liabilities. See Note 10 for further information on hedge accounting and financial derivative instruments.
	The Company classifies its cash collateral provided to or held from counterparties in a “net” presentation on the Consolidated Balance Sheet against the fair value of the derivative positions with those counterparties. See Note 10 for further information.
	Software capitalization
	The Company capitalizes certain internal and external costs related to the acquisition and development of internal use software during the application development stages of projects. The Company amortizes these costs using the straight-line method over the estimated useful life of the software, which typically ranges from five to fifteen years. Costs incurred during the preliminary project or the post-implementation/operation stages of the project are expensed as incurred. Capitalized computer software, included as a component of Ground property and equipment in the accompanying Consolidated Balance Sheet, net of accumulated depreciation, was $403 million and $357 million at December 31, 2014, and 2013, respectively. Computer software depreciation expense was $122 million, $90 million, and $59 million for the years ended December 31, 2014, 2013, and 2012, respectively, and is included as a component of Depreciation and amortization expense in the accompanying Consolidated Statement of Income.
	Income taxes
	The Company accounts for deferred income taxes utilizing an asset and liability method, whereby deferred tax assets and liabilities are recognized based on the tax effect of temporary differences between the financial statements and the tax basis of assets and liabilities, as measured by current enacted tax rates. The Company also evaluates the need for a valuation allowance to reduce deferred tax assets to estimated recoverable amounts.
	The Company’s policy for recording interest and penalties associated with uncertain tax positions is to record such items as a component of income before income taxes. Penalties are recorded in Other (gains) losses, net, and interest paid or received is recorded in Interest expense or Interest income, respectively, in the Consolidated Statement of Income. Amounts recorded for penalties and interest related to uncertain tax positions were immaterial for all years presented.
	Concentration risk
	Approximately 83 percent of the Company’s full-time equivalent Employees are unionized and are covered by collective bargaining agreements. The Company manages this risk by maintaining positive relationships with its Employees and its Employees’ Representatives. The majority of the Company's unionized Employees, including its Pilots, Mechanics, Ramp, Operations, Provisioning and Freight Agents, Flight Attendants, Material Specialists, Dispatchers, Flight Crew Training Instructors, Flight Simulator Technicians, and Facilities Maintenance Technicians are in discussions on labor agreements or have labor agreements which will become amendable within one year. These Employee groups represent approximately 70 percent of the Company’s full-time equivalent Employees as of December 31, 2014.
	The Company attempts to minimize its concentration risk with regards to its cash, cash equivalents, and its investment portfolio. This is accomplished by diversifying and limiting amounts among different counterparties, the type of investment, and the amount invested in any individual security or money market fund.
	To manage risk associated with financial derivative instruments held, the Company selects and will periodically review counterparties based on credit ratings, limits its exposure to a single counterparty, and monitors the market position of the program and its relative market position with each counterparty. The Company also has agreements with counterparties containing early termination rights and/or bilateral collateral provisions whereby security is required if market risk exposure exceeds a specified threshold amount or credit ratings fall below certain levels. Collateral deposits provided to or held from counterparties serve to decrease, but not totally eliminate, the credit risk associated with the Company’s hedging program. See Note 10 for further information.
As of December 31, 2014, the Company operates an all-Boeing fleet, all of which are variations of the Boeing 737. Following the 2011 acquisition of AirTran, the Company also operated a fleet of Boeing 717's, but these aircraft were removed from the Company's operations prior to the end of 2014. See Note 7 for further information. If the Company were unable to acquire additional aircraft or associated aircraft parts from Boeing, or Boeing were unable or unwilling to make timely deliveries of aircraft or to provide adequate support for its products, the Company’s operations would be materially adversely impacted. In addition, the Company would be materially adversely impacted in the event of a mechanical or regulatory issue associated with the Boeing 737 aircraft type, whether as a result of downtime for part or all of the Company’s fleet or because of a negative perception by the flying public. The Company is also dependent on sole suppliers for aircraft engines and certain other aircraft parts and would, therefore, also be materially adversely impacted in the event of the unavailability of, or a mechanical or regulatory issue associated with, engines and other parts.
The Company has historically entered into agreements with some of its co-brand, payment, and loyalty partners that contain exclusivity aspects which place certain confidential restrictions on the Company from entering into certain arrangements with other payment and loyalty partners. These arrangements generally extend for the terms of the partnerships, none of which currently extend beyond May 2017. The Company believes the financial benefits generated by the exclusivity aspects of these arrangements outweigh the risks involved with such agreements.

NEW_ACCOUNTING_PRONOUNCEMENTS

NEW ACCOUNTING PRONOUNCEMENTS	12 Months Ended
	Dec. 31, 2014
Accounting Changes and Error Corrections [Abstract]
NEW ACCOUNTING PRONOUNCEMENTS	NEW ACCOUNTING PRONOUNCEMENTS
	On May 28, 2014, the Financial Accounting Standards Board and the International Accounting Standards Board issued converged guidance on recognizing revenue in contracts with customers. The new guidance establishes a single core principle in the Accounting Standards Update ("ASU") No. 2014-09, which is the recognition of revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. This guidance will affect any reporting organization that either enters into contracts with customers to transfer goods or services or enters into contracts for the transfer of non-financial assets. This ASU is effective for fiscal years, and interim periods within those years, beginning on or after December 15, 2016, and early adoption is not permitted. The Company believes the most significant impacts of this ASU on its accounting will be (i) the elimination of the incremental cost method for frequent flyer accounting, which would require the Company to re-value its liability earned by Customers associated with flights points with a relative fair value approach, and (ii) the requirement that the Company discontinue use of the residual method in allocating funds from the sale of frequent flyer points to business partners in its frequent flyer program, which would also require the adoption of a relative fair value approach. The Company is continuing to evaluate the new guidance and plans to provide additional information about its expected financial impact at a future date.
	On August 27, 2014, the Financial Accounting Standards Board issued ASU No. 2014-15. This standard provides guidance on determining when and how to disclose going-concern uncertainties in the financial statements. The new standard requires management to perform interim and annual assessments of an entity’s ability to continue as a going concern within one year of the date the financial statements are issued. This ASU is effective for fiscal years, and interim periods within those years, beginning on or after December 15, 2016, with early adoption permitted. The Company is evaluating the new guidance and plans to provide additional information about its expected impact at a future date.

NET_INCOME_PER_SHARE

NET INCOME PER SHARE	12 Months Ended
	Dec. 31, 2014
Earnings Per Share [Abstract]
NET INCOME PER SHARE	NET INCOME PER SHARE
	The following table sets forth the computation of basic and diluted net income per share (in millions except per share amounts):
		Year ended December 31,
		2014		2013		2012
	NUMERATOR:
	Net income	$	1,136	$	754	$	421
	Incremental income effect of	4		3		3
	interest on 5.25% convertible notes
	Net income after assumed conversion	$	1,140	$	757	$	424
	DENOMINATOR:
	Weighted-average shares outstanding, basic	687		710		750
	Dilutive effect of Employee stock options and	3		2		1
	restricted stock units
	Dilutive effect of 5.25% convertible notes	6		6		6
	Adjusted weighted-average shares outstanding, diluted	696		718		757
	NET INCOME PER SHARE:
	Basic	$	1.65	$	1.06	$	0.56
	Diluted	$	1.64	$	1.05	$	0.56
	Potentially dilutive amounts excluded from calculations:
	Stock options and restricted stock units	—		9		35

COMMITMENTS_AND_CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	12 Months Ended
	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	COMMITMENTS AND CONTINGENCIES
	Commitments
	The Company has contractual obligations and commitments primarily with regard to future purchases of aircraft, repayment of debt, and lease arrangements. During the year ended December 31, 2014, the Company purchased 33 new 737-800 aircraft from Boeing and 11 used 737-700 aircraft from third parties. In addition, the Company also leased 11 737-700 aircraft from third parties, retired from service five of its older aircraft (three 737-300 and two 737-500), and removed 66 of its 717-200 aircraft from service during 2014. As of December 31, 2014, the Company had firm deliveries and options for Boeing 737-700, 737-800, 737 MAX 7, and 737 MAX 8 aircraft as follows:
		The Boeing Company					The Boeing Company
		737 NG					737 MAX
		-700		-800	Options	Additional -700 A/C	-7	-8		Options	Total
		Firm		Firm			Firm	Firm
		Orders		Orders			Orders	Orders
	2015	—		19	—	16	—	—		—	35
	2016	31		—	11	4	—	—		—	46
	2017	15		—	12	—	—	14		—	41
	2018	10		—	12	—	—	13		—	35
	2019	—		—	—	—	15	10		—	25
	2020	—		—	—	—	14	22		—	36
	2021	—		—	—	—	1	33		18	52
	2022	—		—	—	—	—	30		19	49
	2023	—		—	—	—	—	24		23	47
	2024	—		—	—	—	—	24		23	47
	2025	—		—	—	—	—	—		36	36
	2026	—		—	—	—	—	—		36	36
	2027	—		—	—	—	—	—		36	36
	Total	56	-1	19	35	20	30	170	-2	191	521
	(1) The Company has flexibility to substitute 737-800s in lieu of 737-700 firm orders.
	(2) The Company has flexibility to substitute MAX 7 in lieu of  MAX 8 firm orders beginning in 2019.
	The Company's financial commitments associated with the Boeing firm orders and additional scheduled deliveries in the above aircraft table are as follows: $836 million in 2015, $1.2 billion in 2016, $1.2 billion in 2017, $1.0 billion in 2018, $1.1 billion in 2019, and $5.7 billion thereafter.
	Fort Lauderdale-Hollywood International Airport
	In December 2013, the Company entered into an agreement with Broward County, Florida, which owns and operates Fort Lauderdale-Hollywood International Airport, to oversee and manage the design and construction of the airport's Terminal 1 Modernization Project at a cost not to exceed $295 million. In addition to significant improvements to the existing Terminal 1, the project includes the design and construction of a new five-gate Concourse A with an international processing facility. Funding for the project will come directly from Broward County sources, but will flow through the Company in its capacity as manager of the project. Construction on the project is not expected to begin until mid to late 2015. The Company believes that due to its agreed upon role in overseeing and managing the project, it will be considered the owner of the project for accounting purposes. As such, in the Consolidated Balance Sheet, the Company is expected to record an increase in Assets constructed for others as the project is built, along with a corresponding outflow within Capital expenditures, in the Consolidated Statement of Cash Flows, and an increase to Construction obligation (with a corresponding cash inflow from Financing activities in the Consolidated Statement of Cash Flows) as reimbursements are received from Broward County.
	Houston William P. Hobby Airport
	The Company entered into a Memorandum of Agreement (“MOA”) with the City of Houston (“City”), effective June 2012, to expand the existing Houston Hobby airport facility. As provided in the MOA, the Company and the City have entered into an Airport Use and Lease Agreement (“Lease”) to control the execution of this expansion and the financial terms thereof. Per the MOA and Lease, this project provides for a new five-gate international terminal with international passenger processing facilities, expansion of the existing security checkpoint, and upgrades to the Southwest ticket counter area. The project is estimated to cost $156 million, and the Company has agreed to provide the funding for, as well as management over, the project. In return, the capital cost portion of the rent the Company pays for the international facility will be waived from the initial occupancy until the expiration of the Lease. However, after completion of the project, the City has the option to buy-out Southwest's investment at the then-unamortized cost of the facility. This purchase would trigger payment of the previously waived capital cost component of rents owed the City. Additionally, some portion of the project is expected to qualify for rental credits that would be utilized upon completion of the facility against the Company’s lease payments at the airport. Construction began during third quarter 2013 and is estimated to be completed during the second half of 2015.
	As a result of its significant involvement in the Houston Hobby project, the Company has evaluated its ongoing accounting requirements in consideration of accounting guidance provided for lessees involved in asset construction, and has determined that it qualifies as the accounting owner of the facility during the construction period. As such, during construction, the Company records expenditures as Assets constructed for others in the Consolidated Balance Sheet, along with a corresponding outflow within Capital expenditures, in the Consolidated Statement of Cash Flows. As of December 31, 2014, the Company had recorded construction costs related to Houston Hobby of $64 million.
	Los Angeles International Airport
	In March 2013, the Company executed a lease agreement with Los Angeles World Airports (“LAWA”), which owns and operates Los Angeles International Airport ("LAX"). Under the lease agreement, which was amended in June 2014, the Company will oversee and manage the design, development, financing, construction and commissioning of the airport's Terminal 1 Modernization Project (the “Project”) at a cost not to exceed $525 million. The Project will be funded using the Regional Airports Improvement Corporation ("RAIC"), which is a quasi-governmental special purpose entity which will act as a conduit borrower under a syndicated credit facility provided by a group of lenders. Loans made under the credit facility will be used to fund the development of the Project, and the outstanding loans will be repaid with the proceeds of LAWA’s payments to purchase completed Project phases. The Company has guaranteed the obligations of the RAIC under the credit facility. Construction on the project began during 2014. The Company believes that due to its agreed upon role in overseeing and managing the project, it is considered the owner of the project for accounting purposes. As of December 31, 2014, the Company had recorded construction costs related to LAX of $52 million, which are classified with Assets constructed for others and as Construction obligation in the accompanying Consolidated Balance Sheet.
	Dallas Love Field
	During 2008, the City of Dallas approved the Love Field Modernization Program (“LFMP”), a project to reconstruct Dallas Love Field with modern, convenient air travel facilities. Pursuant to a Program Development Agreement with the City of Dallas and the Love Field Airport Modernization Corporation (or “LFAMC,” a Texas non-profit “local government corporation” established by the City of Dallas to act on the City of Dallas' behalf to facilitate the development of the LFMP), the Company is managing this project. Major construction commenced during 2010. The project consists of the complete replacement of gate facilities with a new 20-gate facility, including infrastructure, systems and equipment, aircraft parking apron, fueling system, roadways and terminal curbside, baggage handling systems, passenger loading bridges and support systems, and other supporting infrastructure. New ticketing and check-in areas opened during fourth quarter 2012, 12 new gates and new concessions opened in 2013, and the remaining gates opened during October 2014. The majority of the project had been completed as of December 31, 2014.
	It is currently expected that the total construction costs associated with the LFMP project will be approximately $519 million. Although the City of Dallas has received commitments from various sources that are helping to fund portions of the LFMP project, including the Federal Aviation Administration (“FAA”), the Transportation Security Administration, and the City of Dallas' Aviation Fund, the majority of the funds used are from the issuance of bonds. During fourth quarter 2010, $310 million of such bonds were issued by the LFAMC, and the Company has guaranteed principal and interest payments on the bonds. An additional tranche of such bonds totaling $146 million was issued during second quarter 2012, and the Company has guaranteed the principal and interest payments on these bonds as well. The Company currently expects that as a result of the funding commitments from the above mentioned sources and the bonds that have been issued thus far, no further bond issuances guaranteed by the Company will be required to complete the LFMP project.
	In conjunction with the Company's significant presence at Dallas Love Field, its rights to occupy 16 of the available gates upon completion of the facility, and other factors, the Company agreed to manage the majority of the LFMP project. In January 2015, the Company announced a long-term sublease agreement that will transfer usage of two additional gates, giving the Company 18 gates in the newly rebuilt 20-gate facility at Dallas Love Field. Based on these facts, the Company evaluated its ongoing accounting requirements in consideration of accounting guidance provided for lessees involved in asset construction. The Company has recorded and will continue to record an asset and corresponding obligation for the cost of the LFMP project until final completion of the project. As of December 31, 2014, the Company had recorded LFMP construction costs of $504 million within Assets constructed for others and had recorded a liability of $501 million within Construction obligation in its Consolidated Balance Sheet. Upon completion of different phases of the LFMP project, the Company has placed the associated assets in service and has begun depreciating the assets over their estimated useful lives. The amount of depreciation recorded for the year ended December 31, 2014, associated with the LFMP assets in service was $20 million. The corresponding LFMP liabilities will be reduced primarily through the Company's airport rental payments to the City of Dallas as the construction costs of the project are passed through to the Company via recurring airport rates and charges. A portion of these payments are reflected as Repayment of construction obligation in the Consolidated Statement of Cash Flows. Further, future contractual airport rental payments to the City of Dallas are included in the schedule of future minimum lease payments in Note 7. The Company records interest expense on the Construction obligation at an imputed rate based on the outstanding bonds.
	The LFMP Construction is the only Asset Constructed for Others which has been placed into service as of December 31, 2014, and its associated projects are estimated to have a weighted average useful life of 27 years and a residual value of 17%.
	Contingencies
	The Company is from time to time subject to various legal proceedings and claims arising in the ordinary course of business, including, but not limited to, examinations by the IRS. The Company's management does not expect that the outcome in any of its currently ongoing legal proceedings or the outcome of any adjustments presented by the IRS, individually or collectively, will have a material adverse effect on the Company's financial condition, results of operations, or cash flow.

SUPPLEMENTAL_FINANCIAL_INFORMA

SUPPLEMENTAL FINANCIAL INFORMATION	12 Months Ended
	Dec. 31, 2014
Disclosure Text Block [Abstract]
SUPPLEMENTAL FINANCIAL INFORMATION	SUPPLEMENTAL FINANCIAL INFORMATION
	(in millions)	31-Dec-14		31-Dec-13
	Derivative contracts	$	13	$	145
	Intangible assets	363		166
	Non-current investments	35		44
	Other	123		175
	Other assets	$	534	$	530
	(in millions)	31-Dec-14		31-Dec-13
	Accounts payable trade	$	123	$	189
	Salaries payable	160		156
	Taxes payable	163		146
	Aircraft maintenance payable	314		331
	Fuel payable	85		102
	Other payable	358		323
	Accounts payable	$	1,203	$	1,247
	(in millions)	31-Dec-14		31-Dec-13
	Profitsharing and savings plans	$	374	$	244
	Aircraft and other lease related obligations	159		173
	Vacation pay	292		278
	Health	84		73
	Derivative contracts	174		12
	Workers compensation	165		161
	Property and other taxes	81		65
	Other	236		223
	Accrued liabilities	$	1,565	$	1,229
	(in millions)	31-Dec-14		31-Dec-13
	Postretirement obligation	$	169	$	138
	Non-current lease-related obligations	193		290
	Other deferred compensation	174		163
	Deferred gains from sale and leaseback of aircraft	53		65
	Derivative contracts	622		45
	Other	44		70
	Other non-current liabilities	$	1,255	$	771
	Other Operating Expenses
	Other operating expenses consist of distribution costs, advertising expenses, personnel expenses, professional fees, and other operating costs, none of which individually exceed 10 percent of Operating expenses.

LONGTERM_DEBT

LONG-TERM DEBT	12 Months Ended
	Dec. 31, 2014
Debt Disclosure [Abstract]
LONG-TERM DEBT	LONG-TERM DEBT
	(in millions)	31-Dec-14		31-Dec-13
	5.25% Notes due 2014	—		357
	5.75% Notes due 2016	313		320
	5.25% Convertible Senior Notes due 2016	113		115
	5.125% Notes due 2017	316		322
	Fixed-rate 717 Aircraft Notes payable through 2017—10.37%	—		41
	French Credit Agreements due 2018—1.06%	36		46
	Fixed-rate 737 Aircraft Notes payable through 2018—7.02%	24		30
	2.75% Notes due 2019	300		—
	Term Loan Agreement due 2019—6.315%	178		210
	Term Loan Agreement due 2019—6.84%	73		85
	Term Loan Agreement due 2020—5.223%	372		413
	Floating-rate 737 Aircraft Notes payable through 2020	300		340
	Pass Through Certificates due 2022—6.24%	355		371
	7.375% Debentures due 2027	134		136
	Capital leases (Note 7)	199		56
		$	2,713	$	2,842
	Less current maturities	258		629
	Less debt discount and issuance costs	21		22
		$	2,434	$	2,191
	AirTran Long-Term Debt
	AirTran Holdings previously entered into aircraft purchase financing facilities, under which a total of 22 737-700 aircraft were financed as of December 31, 2014.
	As of December 31, 2014, after prepaying aircraft secured term loans for eight aircraft during 2012 and the first half of 2013, 19 Boeing 737 aircraft remain that were financed under floating-rate facilities. Each note is secured by a first mortgage on the aircraft to which it relates. The notes bear interest at a floating rate per annum equal to a margin plus the three or six-month LIBOR in effect at the commencement of each semi-annual or three-month period, as applicable. As of December 31, 2014, the weighted average interest rate was 1.66 percent. Principal and interest under the notes are payable semi-annually or every three months as applicable. As of December 31, 2014, the remaining debt outstanding may be prepaid without penalty under all aircraft loans provided under such facilities. The notes mature in years 2016 to 2020. As discussed further in Note 10, a portion of the above floating-rate debt has been effectively converted to a fixed rate via interest rate swap agreements which expire between 2016 and 2020.
	As of December 31, 2014, three Boeing 737 aircraft were financed under a fixed-rate facility. Each note is secured by a first mortgage on the aircraft to which it relates. As of December 31, 2014, the weighted average interest rate was 7.02 percent. Payments of principal and interest under the notes are due semi-annually. The notes mature in years 2016 to 2018.
	As of December 31, 2014, Boeing 717 aircraft previously pledged as collateral for the obligations related to enhanced equipment trust certificates (EETCs) were paid in full. On April 1, 2014, the Company prepaid a portion of its Fixed-rate 717 Aircraft Notes payable in the amount of $35 million prior to their 2017 maturity date. On October 1, 2014, the Company prepaid the remainder of its Fixed-rate 717 Aircraft Notes payable in the amount of $7 million. As a result of the early repayment, the Company incurred a $6 million make-whole penalty, representing the present value of the future interest payments on the notes, which is reflected as a component of Interest expense in the Consolidated Statement of Income. In addition, the Company wrote off the remainder of its unamortized debt premium associated with these notes in second quarter 2014, in the amount of $5 million, which is reflected as a reduction to Interest expense in the Consolidated Statement of Income.
	In October 2009, AirTran Holdings completed a public offering of $115 million of convertible senior notes due in 2016. Such notes bear interest at 5.25 percent payable semi-annually, in arrears, on May 1 and November 1. As a result of the acquisition and subsequent dividends declared by the Company, the convertible senior notes are convertible into AirTran conversion units of 167.5224 per $1,000 in principal amount of such notes. Based on the terms of the merger agreement, the holders of these notes would receive shares of the Company’s common stock at a conversion rate of 53.7747 shares and $615.16 in cash per $1,000 in principal amount of such notes. This conversion rate is subject to adjustment under certain circumstances such as: granting of stock and cash dividends, a make-whole fundamental change of ownership provision, the issuance of rights or warrants, and/or a distribution of capital stock. Subsequent to the acquisition, holders of $5 million in principal amount elected to convert their notes. Remaining holders may convert their convertible senior notes into cash and shares of common stock at their option at any time. As such, the Company has classified $68 million, which is the cash portion the Company would be required to pay upon conversion, as current maturities in the Consolidated Balance Sheet. The convertible senior notes are not redeemable at the Company’s option prior to maturity. The holders of the convertible senior notes may require the Company to repurchase such notes, in whole or in part, for cash upon the occurrence of a fundamental change, as defined in the governing supplemental indenture, at a repurchase price of 100 percent of the principal amount plus any accrued and unpaid interest.
	As a result of triggering the fundamental change of ownership provision in the convertible senior notes and as a result of the acquisition, an embedded conversion option is deemed to exist. In accordance with applicable accounting guidance, the embedded conversion option was effectively separated and accounted for as a free-standing derivative. A fair value calculation, utilizing similar market yields and the Company’s common stock price, was performed for the debt with and without the equity to measure the equity component. The value allocated to the conversion option of $35 million is classified as permanent equity. The estimated premium associated with the notes excluding the equity feature was $10 million, and is being amortized to interest expense over the remaining life of the notes. The dilutive effect of the shares that would be issued if the convertible notes were converted is considered in the Company’s net income per share calculations, unless such conversion would be considered antidilutive. See Note 3.
	Other Company Long-Term Debt
	During November 2014, the Company issued $300 million senior unsecured notes due 2019. The notes bear interest at 2.75 percent, payable semi-annually in arrears on May 6 and November 6. Concurrently, the Company entered into a fixed-to-floating interest rate swap to convert the interest on these unsecured notes to a floating rate until their maturity. See Note 10 for further information on the interest-rate swap agreement.
	On April 29, 2009, the Company entered into a term loan agreement providing for loans to the Company aggregating up to $332 million, to be secured by mortgages on 14 of the Company’s 737-700 aircraft. The Company borrowed the full $332 million and secured the loan with the requisite 14 aircraft mortgages. The loan matures on May 6, 2019, and is being repaid via quarterly installments of principal that began August 6, 2009. The loan bears interest at the LIBO Rate (as defined in the term loan agreement) plus 3.30 percent, and interest is payable quarterly, which payments began on August 6, 2009. Pursuant to the terms of the term loan agreement, the Company entered into an interest rate swap agreement to convert the variable rate on the term loan to a fixed 6.315 percent until maturity.
	On July 1, 2009, the Company entered into a term loan agreement providing for loans to the Company aggregating up to $124 million, to be secured by mortgages on five of the Company’s 737-700 aircraft. The Company has borrowed the full $124 million and secured this loan with the requisite five aircraft mortgages. The loan matures on July 1, 2019, and is repayable semi-annually in installments of principal that began January 1, 2010. The loan bears interest at a fixed rate of 6.84 percent, and interest is payable semi-annually, which payments began on January 1, 2010.
	On May 6, 2008, the Company entered into a term loan agreement providing for loans to the Company aggregating up to $600 million, to be secured by first-lien mortgages on 21 of the Company’s 737-700 aircraft. On May 9, 2008, the Company borrowed the full $600 million and secured these loans with the requisite 21 aircraft mortgages. The loans mature on May 9, 2020, and are repayable quarterly in installments of principal, with the first payment made on August 9, 2008. The loans bear interest at the LIBO Rate (as defined in the term loan agreement) plus 0.95 percent, and interest is payable quarterly. Pursuant to the terms of the term loan agreement, the Company entered into an interest rate swap agreement to convert the variable rate on the term loan to a fixed 5.223 percent until maturity.
	On October 3, 2007, grantor trusts established by the Company issued $500 million Pass Through Certificates consisting of $412 million 6.15% Series A certificates and $88 million 6.65% Series B certificates. A separate trust was established for each class of certificates. The trusts used the proceeds from the sale of certificates to acquire equipment notes in the same amounts, which were issued by the Company on a full recourse basis. Payments on the equipment notes held in each trust will be passed through to the holders of certificates of such trust. The equipment notes were issued for each of 16 Boeing 737-700 aircraft owned by the Company and are secured by a mortgage on each aircraft. Interest on the equipment notes held for the certificates is payable semi-annually, with the first payment made on February 1, 2008. Also beginning February 1, 2008, principal payments on the equipment notes held for both series of certificates are due semi-annually until the balance of the certificates mature on August 1, 2022. Prior to their issuance, the Company also entered into swap agreements to hedge the variability in interest rates on the Pass Through Certificates. The swap agreements were accounted for as cash flow hedges, and resulted in a payment by the Company of $20 million upon issuance of the Pass Through Certificates. The effective portion of the hedge is being amortized to interest expense concurrent with the amortization of the debt and is reflected in the above table as a reduction in the debt balance. The ineffectiveness of the hedge transaction was immaterial.
	During December 2006, the Company issued $300 million senior unsecured notes due 2016. The notes bear interest at 5.75 percent, payable semi-annually in arrears, with the first payment made on June 15, 2007. During fourth quarter 2009, the Company entered into a fixed-to-floating interest rate swap to convert the interest on these unsecured notes to a floating rate until their maturity. See Note 10 for further information on the interest-rate swap agreement.
	During February 2005, the Company issued $300 million senior unsecured notes due 2017. The notes bear interest at 5.125 percent, payable semi-annually in arrears, with the first payment made on September 1, 2005.
	In fourth quarter 2004, the Company entered into four identical 13-year floating-rate financing arrangements, whereby it borrowed a total of $112 million from French banking partnerships. Although the interest rates on the borrowings float, the Company estimated at inception that, considering the full effect of the “net present value benefits” included in the transactions, the effective economic yield over the 13-year term of the loans will be approximately LIBOR minus 45 basis points. Principal and interest are payable semi-annually on June 30 and December 31 for each of the loans, and the Company may terminate the arrangements in any year on either of those dates, under certain conditions. The Company pledged four aircraft as collateral for the transactions.
	In September 2004, the Company issued $350 million senior unsecured notes due 2014. The notes matured and were redeemed in full on October 1, 2014, utilizing available cash on hand.
	On February 28, 1997, the Company issued $100 million of senior unsecured 7.375% debentures due March 1, 2027. Interest is payable semi-annually on March 1 and September 1. The debentures may be redeemed, at the option of the Company, in whole at any time or in part from time to time, at a redemption price equal to the greater of the principal amount of the debentures plus accrued interest at the date of redemption or the sum of the present values of the remaining scheduled payments of principal and interest thereon, discounted to the date of redemption at the comparable treasury rate plus 20 basis points, plus accrued interest at the date of redemption. In January 2007, the Company entered into an interest rate swap agreement to convert this fixed-rate debt to a floating rate; however, the interest rate swap was terminated in December 2012. See Note 10 for more information on the interest rate swap agreement and termination.
	The Company is required to provide standby letters of credit to support certain obligations that arise in the ordinary course of business. Although the letters of credit are an off-balance sheet item, the majority of the obligations to which they relate are reflected as liabilities in the Consolidated Balance Sheet. Outstanding letters of credit totaled $440 million at December 31, 2014.
	The net book value of the assets pledged as collateral for the Company’s secured borrowings, primarily aircraft and engines, was $2.0 billion at December 31, 2014. In addition, the Company has pledged a total of up to 81 of its Boeing 737-700 aircraft at a net book value of $2.0 billion, in the case that it has obligations related to its fuel derivative instruments with counterparties that exceed certain thresholds. See Note 10 for further information on these collateral arrangements.
	As of December 31, 2014, aggregate annual principal maturities of debt and capital leases (not including amounts associated with interest rate swap agreements, interest on capital leases, amortization of capital lease incentives, and amortization of purchase accounting adjustments) for the five-year period ending December 31, 2019 and thereafter, were $182 million in 2015, $610 million in 2016, $520 million in 2017, $264 million in 2018, $514 million in 2019, and $551 million thereafter.

LEASES

LEASES	12 Months Ended
	Dec. 31, 2014
Leases [Abstract]
LEASES	LEASES
	The Company's fleet includes 16 aircraft on capital lease, including two B717s, as of December 31, 2014, compared with four aircraft on capital lease as of December 31, 2013. Amounts applicable to these aircraft that are included in property and equipment were:
	(in millions)	2014			2013
	Flight equipment	$	214		$	69
	Less: accumulated amortization	22			12
		$	192		$	57
	Total rental expense for operating leases, both aircraft and other, charged to operations in 2014, 2013, and 2012 was $931 million, $997 million, and $943 million, respectively. The majority of the Company’s terminal operations space, as well as 174 aircraft, which includes 76 B717s, were under operating leases at December 31, 2014. For aircraft operating leases and for terminal operations leases, expense is included in Aircraft rentals and in Landing fees and other rentals, respectively, in the Consolidated Statement of Income. Future minimum lease payments under capital leases and noncancelable operating leases and rentals to be received under subleases with initial or remaining terms in excess of one year at December 31, 2014, were:
	(in millions)	Capital			Operating		Subleases			LFMP facility lease*		Operating
		leases			leases							leases, net
	2015	$	33		$	753	$	(93	)	$	24	$	684
	2016	42			715		(103		)	24		636
	2017	45			671		(103		)	24		592
	2018	44			573		(102		)	25		496
	2019	43			502		(97		)	25		430
	Thereafter	202			1,802		(144		)	659		2,317
	Total minimum lease payments	$	409		$	5,016	$	(642	)	$	781	$	5,155
	Less amount representing interest	75
	Present value of minimum lease payments	334
	Less current portion	23
	Long-term portion	$	311
	* See Note 4 for further details
	The aircraft leases generally can be renewed for one to five years at rates based on fair market value at the end of the lease term. Most aircraft leases have purchase options at or near the end of the lease term at fair market value, generally limited to a stated percentage of the lessor’s defined cost of the aircraft.
	During fourth quarter 2013, the Company entered into sale and leaseback transactions with a third party aircraft lessor for the sale and leaseback of two Boeing 737-800 aircraft. The transactions were closed on the date of delivery from Boeing, and resulted in the delivery payments being made by the aircraft lessor directly to Boeing, and Southwest being refunded the $12 million in progress payments it had previously made to Boeing during the period the aircraft was being constructed. These transactions resulted in deferred gains that are not material, which are being amortized over the terms of the respective leases, which are both 11 years. Both of the leases from these sale and leaseback transactions are accounted for as operating leases. Under the terms of the lease agreements, the Company will continue to operate and maintain the aircraft. Payments under the lease agreements are fixed. The lease agreements contain standard termination events, including termination upon a breach of the Company's obligations to make rental payments and upon any other material breach of the Company's obligations under the leases, and standard maintenance and return condition provisions. Upon a termination of the lease due to a breach by the Company, the Company would be liable for standard contractual damages, possibly including damages suffered by the lessor in connection with remarketing the aircraft or while the aircraft is not leased to another party.
	On July 9, 2012, the Company signed an agreement with Delta Air Lines, Inc. and Boeing Capital Corp. to lease or sublease all 88 of AirTran's B717s to Delta at agreed-upon lease rates. The first converted B717 was delivered to Delta in September 2013, and as of December 31, 2014, the Company had delivered a total of 52 B717s to Delta. Over the expected term of the transition period for all B717s, the Company expects to average approximately three B717 conversions per month; however, as the Company previously announced, all B717s remaining at Southwest were grounded on December 28, 2014. A portion of the B717 fleet that will not be delivered to Delta until the second half of 2015 has been placed in storage until each aircraft is ready to be converted. A total of 76 of the B717s are on operating lease, ten are owned, and two are on capital lease.
	The Company has paid and will continue to pay the majority of the costs to convert the aircraft to the Delta livery and perform certain maintenance checks prior to the delivery of each aircraft. The agreement to pay these conversion and maintenance costs is a “lease incentive” under applicable accounting guidance. The sublease terms for the 76 B717s on operating lease and the two B717s on capital lease coincide with the Company's remaining lease terms for these aircraft from the original lessor, which range from approximately three to nine years. The leasing of the ten B717s that are owned by the Company is subject to certain conditions, and the lease terms are for seven years, after which Delta will have the option to purchase the aircraft at the then-prevailing market value. The Company accounts for the lease and sublease transactions with Delta as operating leases, except for the two aircraft classified by the Company as capital leases. The subleases of the two capital lease aircraft are accounted for as direct financing leases. There are no contingent payments and no significant residual value conditions associated with the transaction.
	The accounting for this transaction is based on the guidance provided for lease transactions. For the components of this transaction finalized in third quarter 2012 and with respect to which the lease inception has been deemed to occur, the Company recorded a charge of approximately $137 million during third quarter 2012. The charge represents the remaining estimated cost, at the scheduled date of delivery of each B717 to Delta (including the conversion, maintenance, and other contractual costs to be incurred), of the Company's lease of the 76 B717s that are accounted for as operating leases, net of the future sublease income from Delta and the remaining unfavorable aircraft lease liability established as of the acquisition date. During 2014, the Company recorded an additional $22 million in expense for its revised estimate of conversion costs for these B717s. The charges recorded by the Company for this transaction were included as a component of Acquisition and integration costs in the Company's Consolidated Statement of Income and were included as a component of Other, net in Cash flows from operating activities in the Company's Consolidated Statement of Cash Flows, and the corresponding liability for this transaction is included as a component of Current liabilities and Other noncurrent liabilities in the Company's Consolidated Balance Sheet. A rollforward of the Company's B717 lease/sublease liability for 2014 and 2013 is shown below:
	(in millions)	B717 lease/sublease liability
	Balance at December 31, 2012	$	128
	Lease/sublease accretion	6
	Lease/sublease payments, net (a)	(12		)
	Balance at December 31, 2013	$	122
	Lease/sublease accretion	5
	Lease/sublease expense adjustment	22
	Lease/sublease payments, net (a)	(86		)
	Balance at December 31, 2014	$	63
	(a) Includes lease conversion cost payments
	The Company halted service of its B717 fleet as of December 28, 2014, and as a result recorded an additional $9 million charge associated with the extension of the time between when the Company removed the aircraft from revenue service and when they enter the conversion process.

COMMON_STOCK

COMMON STOCK	12 Months Ended
	Dec. 31, 2014
Equity [Abstract]
COMMON STOCK	COMMON STOCK
	The Company has one class of capital stock, its common stock. Holders of shares of common stock are entitled to receive dividends when and if declared by the Board of Directors and are entitled to one vote per share on all matters submitted to a vote of the Shareholders. At December 31, 2014, the Company had 47 million shares of common stock reserved for issuance pursuant to Employee equity plans (of which 20 million shares had not been granted) through various share-based compensation arrangements. See Note 9 to the Consolidated Financial Statements for information regarding the Company's equity plans.

STOCK_PLANS

STOCK PLANS	12 Months Ended
	Dec. 31, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
STOCK PLANS	STOCK PLANS
	Share-based compensation
	The Company accounts for share-based compensation utilizing fair value. The Consolidated Statement of Income for the years ended December 31, 2014, 2013, and 2012, reflects share-based compensation expense of $21 million, $18 million, and $16 million, respectively. The total tax benefit recognized in earnings from share-based compensation arrangements for the years ended December 31, 2014, 2013, and 2012, was not material. As of December 31, 2014, there was $33 million of total unrecognized compensation cost related to share-based compensation arrangements, which is expected to be recognized over a weighted-average period of 1.1 years.
	Restricted stock units and stock grants
	Under the Company’s Amended and Restated 2007 Equity Incentive Plan (“2007 Equity Plan”), it granted restricted stock units (“RSUs”) to certain Employees during 2012, 2013, and 2014 and performance-based restricted stock units (“PBRSUs”) to certain Employees during 2014. The fair value of RSUs and PBRSUs is based on the closing price of the Company’s common stock on the date of grant. Outstanding RSUs vest over three years, subject generally to the individual’s continued employment or service. The PBRSUs vest on May 14, 2017, subject to the Company’s performance with respect to a three-year simple average of Return on Invested Capital, before taxes and excluding special items ("ROIC"), for the period beginning on January 1, 2014 and ending on December 31, 2016, and the individual’s continued employment or service. The number of PBRSUs vesting on the vesting date will be interpolated based on the average ROIC for the defined performance period, and ranges from zero PBRSUs at an average ROIC of 12 percent or lower to 200 percent of granted PBRSUs at an average ROIC of 20 percent or higher. The Company recognizes all expense on a straight-line basis over the vesting period, with any changes in expense due to the number of PBRSUs expected to vest being modified on a prospective basis.
	In addition, the Company granted approximately 36 thousand shares of unrestricted stock at a weighted average grant price of $24.91 in 2014, approximately 63 thousand shares at a weighted average grant price of $14.34 in 2013, and approximately 82 thousand shares at a weighted average grant price of $8.21 in 2012, to members of its Board of Directors. The fair value of unrestricted stock grants is also based on the closing price of the Company’s common stock on the date of grant.
	A remaining balance of up to ten million shares of the Company’s common stock may be issued pursuant to grants under the 2007 Equity Plan. Aggregated information regarding the Company’s RSUs and PBRSUs is summarized below:
		All Restricted Stock Units
		Units (000)			Wtd. Average
					Fair Value
					(per share)
	Outstanding December 31, 2011, Unvested	1,640			$	12.27
	Granted	1,939			8.21
	Vested	(644	)		12.27
	Surrendered	(59	)		10.54
	Outstanding December 31, 2012	2,876			9.57
	Granted	1,139			14.34
	Vested	(1,263	)		10.24
	Surrendered	(168	)		9.11
	Outstanding December 31, 2013	2,584			11.38
	Granted	834		(a)	24.93
	Vested	(1,239	)		11.05
	Surrendered	(102	)		13.18
	Outstanding December 31, 2014, Unvested	2,077			$	16.92
	(a) Includes 198 thousand shares of PBRSUs
	Stock options
	The Company has previously awarded stock options under plans covering Employees subject to collective bargaining agreements (collective bargaining plans) and plans covering other Employees and members of the Board of Directors (other Employee plans). None of the collective bargaining plans were required to be approved by Shareholders. Options granted to Employees under collective bargaining plans are non-qualified, granted at or above the fair value of the Company’s common stock on the date of grant, and generally have terms ranging from six to twelve years. There were no material grants of stock options to Employees covered by collective bargaining plans during 2012, 2013, or 2014, and no future option grants from these plans are possible. Neither Executive Officers nor members of the Company’s Board of Directors are eligible to participate in any of the collective bargaining plans. Options granted to Employees and members of the Board of Directors through other Employee plans are both qualified as incentive stock options under the Internal Revenue Code of 1986 and non-qualified stock options, granted at no less than the fair value of the Company’s common stock on the date of grant, and have 10-year terms. All of the options included in other Employee plans have been approved by Shareholders, except one plan covering non-management, non-contract Employees, which did not require Shareholder approval and had an insignificant number of options outstanding as of December 31, 2014. Although the Company does not have a formal policy, upon option exercise, the Company will typically issue treasury stock, to the extent such shares are available.
	For other Employee plans, options vest and generally become fully exercisable over three, five, or ten years of continued employment, depending upon the grant type. For grants in any of the Company’s plans that are subject to graded vesting over a service period, the Company recognizes expense on a straight-line basis over the requisite service period for the entire award. None of the Company’s stock option grants include performance-based or market-based vesting conditions, as defined.
	The Black-Scholes option valuation model was developed for use in estimating the fair value of short-term traded options that have no vesting restrictions and are fully transferable. In addition, option valuation models require the input of subjective assumptions including expected stock price volatility. The Company estimates expected stock price volatility via observations of both historical volatility trends as well as implied future volatility observations as determined by independent third parties. Stock options issued by the Company during 2014, 2013, and 2012 were immaterial.
	Aggregated information regarding Company issued stock options is summarized below:
		Stock Option Plans
		Options			Wtd.		Wtd.	Aggregate
		0			average		average	intrinsic
					exercise		remaining	value
					price		contractual	(millions)
							term
							(years)
	Outstanding December 31, 2011	47,324			$	14.51
	Granted	6			9
	Exercised	(573	)		8
	Surrendered	(27,847	)		14.85
	Outstanding December 31, 2012	18,910			$	14.19
	Granted	—			—
	Exercised	(6,633	)		13.31
	Surrendered	(3,116	)		14.94
	Outstanding December 31, 2013	9,161			$	14.58
	Granted	—			—
	Exercised	(6,636	)		14.36
	Surrendered	(48	)		15.74
	Outstanding December 31, 2014	2,477			$	15.17	1.62	$	67
	Vested or expected to vest at December 31, 2014	2,473			$	15.16	1.63	$	67
	Exercisable at December 31, 2014	2,308			$	15.05	1.67	$	63
	The total aggregate intrinsic value of options exercised for all plans during the years ended December 31, 2014, 2013, and 2012, was $75 million, $22 million, and $1 million, respectively. The total grant date fair value of shares vesting during the years ended December 31, 2014, 2013, and 2012, was $15 million, $16 million, and $13 million, respectively.
	Employee Stock Purchase Plan
	Under the amended 1991 Employee Stock Purchase Plan (ESPP), which has been approved by Shareholders, the Company is authorized to issue up to a remaining balance of 11 million shares of the Company’s common stock to Employees of the Company. These shares may be issued at a price equal to 90 percent of the market value at the end of each monthly purchase period. Common stock purchases are paid for through periodic payroll deductions. For the years ended December 31, 2014, 2013, and 2012, participants under the plan purchased 792 thousand shares, 1.5 million shares, and 2.2 million shares at average prices of $23.17, $12.03, and $8.01, respectively. The weighted-average fair value of each purchase right under the ESPP granted for the years ended December 31, 2014, 2013, and 2012, which is equal to the ten percent discount from the market value of the Common Stock at the end of each monthly purchase period, was $2.68, $1.34, and $0.89, respectively.
	Taxes
	A portion of the Company’s granted options qualify as incentive stock options for income tax purposes. As such, a tax benefit is not recorded at the time the compensation cost related to the options is recorded for book purposes due to the fact that an incentive stock option does not ordinarily result in a tax benefit unless there is a disqualifying disposition. Grants of non-qualified stock options result in the creation of a deferred tax asset, which is a temporary difference, until the time that the option is exercised. Due to the treatment of incentive stock options for tax purposes, the Company’s effective tax rate from year to year is subject to variability.

FINANCIAL_DERIVATIVE_INSTRUMEN

FINANCIAL DERIVATIVE INSTRUMENTS	12 Months Ended
	Dec. 31, 2014
Derivative Instruments and Hedging Activities Disclosure [Abstract]
FINANCIAL DERIVATIVE INSTRUMENTS	FINANCIAL DERIVATIVE INSTRUMENTS
	Fuel contracts
	Airline operators are inherently dependent upon energy to operate and, therefore, are impacted by changes in jet fuel prices. Furthermore, jet fuel and oil typically represent one of the largest operating expenses for airlines. The Company endeavors to acquire jet fuel at the lowest possible cost and to reduce volatility in operating expenses through its fuel hedging program. Although the Company may periodically enter into jet fuel derivatives for short-term timeframes, because jet fuel is not widely traded on an organized futures exchange, there are limited opportunities to hedge directly in jet fuel for time horizons longer than approximately 24 months into the future. However, the Company has found that financial derivative instruments in other commodities, such as West Texas Intermediate (“WTI”) crude oil, Brent crude oil, and refined products, such as heating oil and unleaded gasoline, can be useful in decreasing its exposure to jet fuel price volatility. The Company does not purchase or hold any financial derivative instruments for trading or speculative purposes.
	The Company has used financial derivative instruments for both short-term and long-term time frames, and primarily uses a mixture of purchased call options, collar structures (which include both a purchased call option and a sold put option), call spreads (which include a purchased call option and a sold call option), put spreads (which include a purchased put option and a sold put option), and fixed price swap agreements in its portfolio. Although the use of collar structures and swap agreements can reduce the overall cost of hedging, these instruments carry more risk than purchased call options in that the Company could end up in a liability position when the collar structure or swap agreement settles. With the use of purchased call options and call spreads, the Company cannot be in a liability position at settlement, but may be exposed to price changes beyond a certain market price or below.
	The Company evaluates its hedge volumes strictly from an “economic” standpoint and thus does not consider whether the hedges have qualified or will qualify for hedge accounting. The Company defines its “economic” hedge as the net volume of fuel derivative contracts held, including the impact of positions that have been offset through sold positions, regardless of whether those contracts qualify for hedge accounting. The level at which the Company is hedged for a particular period is also dependent on current market prices for that period as well as the types of derivative instruments held and the strike prices of those instruments. For example, the Company may enter into “out-of-the-money” option contracts (including catastrophic protection), which may not generate intrinsic gains at settlement if market prices do not rise above the option strike price. Therefore, even though the Company may have an “economic” hedge in place for a particular period, that hedge may not produce any hedging gains and may even produce hedging losses depending on market prices, the types of instruments held, and the strike prices of those instruments.
	For 2014, the Company had fuel derivative instruments in place for up to 34 percent of its fuel consumption, and, as a result, recognized $56 million in cash gains in Fuel expense from the settlement of those positions. As of December 31, 2014, the Company has reduced its hedge position related to future years, and thus has no "economic" hedge in place for its 2015 estimated fuel consumption. This reduction in the Company's hedge primarily was accomplished through entering into offsetting derivatives that will also settle in the same periods as the economic hedge derivative. Although a portion of the offsetting derivatives were sold swap positions and thus required no cash payment, the Company did pay $217 million to counterparties during fourth quarter 2014 to purchase offsetting derivatives that will settle in 2015 and 2018. These payments effectively serve to reduce the payments to counterparties that would have been required when the original economic derivatives settle in those future periods. However, to the extent the Company utilized hedge accounting for these original derivatives, any losses that had been recorded in AOCI will remain there and be reclassified to earnings in the periods in which the derivatives settle. Also see Note 12 for further information on AOCI. The following table provides information about the Company’s volume of fuel hedging for the years 2015 through 2018 on an “economic” basis considering current market prices:
			Fuel hedged as of
			31-Dec-14			Derivative underlying commodity type as of
	Period (by year)		(gallons in millions)			31-Dec-14
	2015		—		(b)
	2016		885		(a)	Brent crude oil, Heating oil, and Gulf Coast jet fuel
	2017		757		(a)	WTI crude and Brent crude oil
	2018		—		(b)
	(a) Due to the types of derivatives utilized by the Company and different price levels of those contracts, these volumes represent the maximum economic hedge in place and may vary significantly as market prices fluctuate.
	(b) In response to the precipitous decline in oil and jet fuel prices during the second half of 2014, the Company took action to offset its 2015 and 2018 fuel derivative portfolios and is now effectively unhedged at current price levels. While the Company still holds derivative contracts as of December 31, 2014, that will settle during 2015 and 2018, the majority of the losses associated with those contracts are substantially locked in. However, if market prices were to increase or decrease significantly related to the 2015 positions prior to these contracts settling, the losses incurred at settlement could be slightly lower or higher than currently expected amounts during that period.
	Upon proper qualification, the Company accounts for its fuel derivative instruments as cash flow hedges. Generally, utilizing hedge accounting, all periodic changes in fair value of the derivatives designated as hedges that are considered to be effective are recorded in Accumulated Other Comprehensive Income (Loss) ("AOCI") until the underlying jet fuel is consumed. See Note 12. The Company’s results are subject to the possibility that periodic changes will not be effective, as defined, or that the derivatives will no longer qualify for hedge accounting. Ineffectiveness results when the change in the fair value of the derivative instrument exceeds the change in the value of the Company’s expected future cash outlay to purchase and consume jet fuel. To the extent that the periodic changes in the fair value of the derivatives are ineffective, the ineffective portion is recorded to Other (gains) losses, net in the Consolidated Statement of Income. Likewise, if a hedge ceases to qualify for hedge accounting, any change in the fair value of derivative instruments since the last reporting period is recorded to Other (gains) losses, net, in the Consolidated Statement of Income in the period of the change; however, any amounts previously recorded to AOCI would remain there until such time as the original forecasted transaction occurs, at which time these amounts would be reclassified to Fuel and oil expense. When the Company has sold derivative positions in order to effectively “close” or offset a derivative already held as part of its fuel derivative instrument portfolio, any subsequent changes in fair value of those positions are marked to market through earnings. Likewise, any changes in fair value of those positions that were offset by entering into the sold positions and were de-designated as hedges, are concurrently marked to market through earnings. However, any changes in value related to hedges that were deferred as part of AOCI while designated as a hedge would remain until the originally forecasted transaction occurs. In a situation where it becomes probable that a fuel hedged forecasted transaction will not occur, any gains and/or losses that have been recorded to AOCI would be required to be immediately reclassified into earnings. The Company did not have any such situations occur during 2012, 2013, or 2014.
	In some situations, an entire commodity type used in hedging may cease to qualify for special hedge accounting treatment. As an example, during 2013, the Company's routine statistical analysis performed to determine which commodities qualify for special hedge accounting treatment on a prospective basis dictated that WTI crude oil based derivatives no longer qualify for hedge accounting. This is primarily due to the fact that the correlation between WTI crude oil prices and jet fuel prices during recent periods has not been as strong as in the past, and therefore the Company can no longer demonstrate that derivatives based on WTI crude oil prices will result in effective hedges on a prospective basis. As such, the change in fair value of all of the Company's derivatives based in WTI have been recorded to Other (gains) losses subsequent to July 1, 2013, and all future changes in the fair value of such instruments will continue to be recorded directly to earnings in future periods. The change in fair value of the Company's WTI derivative contracts during 2014 was a decrease of $45 million, which resulted in a loss in the Consolidated Statement of Income. The change in fair value of the Company's WTI derivative contracts during the second half of 2013 was an increase of $15 million, which resulted in a gain in the Consolidated Statement of Income. Any amounts previously recorded to AOCI will remain there until such time as the original forecasted transaction occurs in accordance with hedge accounting requirements. The Company will continue to evaluate whether it can qualify for hedge accounting for WTI derivative contracts in future periods.
	Ineffectiveness is inherent in hedging jet fuel with derivative positions based in other crude oil related commodities. Due to the volatility in markets for crude oil and related products, the Company is unable to predict the amount of ineffectiveness each period, including the loss of hedge accounting, which could be determined on a derivative by derivative basis or in the aggregate for a specific commodity. This may result, and has resulted, in increased volatility in the Company’s financial results. Factors that have and may continue to lead to ineffectiveness and unrealized gains and losses on derivative contracts include: significant fluctuation in energy prices, the number of derivative positions the Company holds, significant weather events affecting refinery capacity and the production of refined products, and the volatility of the different types of products the Company uses in hedging. However, even though derivatives may not qualify for hedge accounting, the Company continues to hold the instruments as management believes derivative instruments continue to afford the Company the opportunity to stabilize jet fuel costs.
	Accounting pronouncements pertaining to derivative instruments and hedging are complex with stringent requirements, including the documentation of a Company hedging strategy, statistical analysis to qualify a commodity for hedge accounting both on a historical and a prospective basis, and strict contemporaneous documentation that is required at the time each hedge is designated by the Company. The Company also examines the effectiveness of each individual hedge and its entire hedging program on a quarterly basis utilizing statistical analysis. This analysis involves utilizing regression and other statistical analyses that compare changes in the price of jet fuel to changes in the prices of the commodities used for hedging purposes.
	All cash flows associated with purchasing and selling fuel derivatives are classified as Other operating cash flows in the Consolidated Statement of Cash Flows. The following table presents the location of all assets and liabilities associated with the Company’s hedging instruments within the Consolidated Balance Sheet:
					Asset derivatives								Liability derivatives
			Balance Sheet		Fair value at				Fair value at				Fair value at				Fair value at
	(in millions)		location		12/31/14				12/31/13				12/31/14				12/31/13
	Derivatives designated as hedges*
	Fuel derivative contracts (gross)		Prepaid expenses and other current assets		$	—			$	74			$	—			$	—
	Fuel derivative contracts (gross)		Other assets		—				209				—				1
	Fuel derivative contracts (gross)		Other noncurrent liabilities		—				—				643				—
	Interest rate derivative contracts		Other assets		13				20				—				—
	Interest rate derivative contracts		Other noncurrent liabilities		—				—				61				77
	Total derivatives designated as hedges				$	13			$	303			$	704			$	78
	Derivatives not designated as hedges*
	Fuel derivative contracts (gross)		Prepaid expenses and other current assets		$	—			$	175			$	—			$	182
	Fuel derivative contracts (gross)		Other assets		—				16				—				99
	Fuel derivative contracts (gross)		Accrued liabilities		1,190				9				1,432				21
	Fuel derivative contracts (gross)		Other noncurrent liabilities		157				—				273				—
	Total derivatives not designated as hedges				$	1,347			$	200			$	1,705			$	302
	Total derivatives				$	1,360			$	503			$	2,409			$	380
	* Represents the position of each trade before consideration of offsetting positions with each counterparty and does not include the impact of cash collateral deposits provided to or received from counterparties. See discussion of credit risk and collateral following in this Note.
	In addition, the Company also had the following amounts associated with fuel derivative instruments and hedging activities in its Consolidated Balance Sheet:
			Balance Sheet		December 31,				December 31,
	(in millions)		location		2014				2013
	Cash collateral deposits provided to counterparties for fuel		Offset against Accrued liabilities		$	68			$	—
	contracts - current
	Cash collateral deposits provided to counterparties for fuel		Offset against Other noncurrent liabilities		198				—
	contracts- noncurrent
	Cash collateral deposits provided to counterparties for interest		Offset against Other noncurrent liabilities		—				32
	rate contracts - noncurrent
	Due to third parties for fuel contracts		Accrued liabilities		16				—
	Receivable from third parties for fuel contracts - current		Accounts and other receivables		—				57
	All of the Company's fuel derivative instruments and interest rate swaps are subject to agreements that follow the netting guidance in the applicable accounting for derivatives and hedging. The types of derivative instruments the Company has determined are subject to netting requirements in the accompanying Consolidated Balance Sheet are those in which the Company pays or receives cash for transactions with the same counterparty and in the same currency via one net payment or receipt. For cash collateral held by the Company or provided to counterparties, the Company nets such amounts against the fair value of the Company's derivative portfolio by each counterparty. The Company has elected to utilize netting for both its fuel derivative instruments and interest rate swap agreements and also classifies such amounts as either current or noncurrent, based on the net fair value position with each of the Company's counterparties in the Consolidated Balance Sheet.
	The Company's application of its netting policy associated with cash collateral differs depending on whether its derivative instruments are in a net asset position or a net liability position. If its fuel derivative instruments are in a net asset position with a counterparty, cash collateral amounts held are first netted against current outstanding derivative amounts associated with that counterparty until that balance is zero, and then any remainder is applied against the fair value of noncurrent outstanding derivative instruments. If the Company's fuel derivative instruments are in a net liability position with the counterparty, cash collateral amounts provided are first netted against noncurrent outstanding derivative amounts associated with that counterparty until that balance is zero, and then any remainder is applied against the fair value of current outstanding derivative instruments.
	The Company has the following recognized financial assets and financial liabilities resulting from those transactions that meet the scope of the disclosure requirements as necessitated by applicable accounting guidance for balance sheet offsetting:
	Offsetting of derivative assets
	(in millions)
					(i)				(ii)				(iii) =i) + (ii)				(i)				(ii)				(iii) =i) + (ii)
					December 31, 2014												31-Dec-13
	Description		Balance Sheet location		Gross amounts of recognized assets				Gross amounts offset in the Balance Sheet				Net amounts of assets presented in the Balance Sheet				Gross amounts of recognized assets				Gross amounts offset in the Balance Sheet				Net amounts of assets presented in the Balance Sheet
	Fuel derivative contracts		Prepaid expenses and other current assets		$	—			$	—			$	—			$	249			$	(182	)		$	67
	Fuel derivative contracts		Other assets		$	—			$	—			$	—		(a)	$	225			$	(100	)		$	125		(a)
	Fuel derivative contracts		Accrued liabilities		$	1,258			$	(1,258	)		$	—		(a)	$	9			$	(9	)		$	—		(a)
	Fuel derivative contracts		Other noncurrent liabilities		$	355			$	(355	)		$	—		(a)	$	—			$	—			$	—		(a)
	Interest rate derivative contracts		Other assets		$	13			$	—			$	13		(a)	$	20			$	—			$	20		(a)
	(a) The net amounts of derivative assets and liabilities are reconciled to the individual line item amounts presented in the Consolidated Balance Sheet in Note 5.
	Offsetting of derivative liabilities
(in millions)
				(i)				(ii)				(iii) =i) + (ii)				(i)				(ii)				(iii) =i) + (ii)
				December 31, 2014												31-Dec-13
Description		Balance Sheet location		Gross amounts of recognized liabilities				Gross amounts offset in the Balance Sheet				Net amounts of liabilities presented in the Balance Sheet				Gross amounts of recognized liabilities				Gross amounts offset in the Balance Sheet				Net amounts of liabilities presented in the Balance Sheet
Fuel derivative contracts		Prepaid expenses and other current assets		$	—			$	—			$	—			$	182			$	(182	)		$	—
Fuel derivative contracts		Other assets		$	—			$	—			$	—		(a)	$	100			$	(100	)		$	—		(a)
Fuel derivative contracts		Accrued liabilities		$	1,432			$	(1,258	)		$	174		(a)	$	21			$	(9	)		$	12		(a)
Fuel derivative contracts		Other noncurrent liabilities		$	916			$	(355	)		$	561		(a)	$	—			$	—			$	—		(a)
Interest rate derivative contracts		Other noncurrent liabilities		$	61			$	—			$	61		(a)	$	77			$	(32	)		$	45		(a)
(a) The net amounts of derivative assets and liabilities are reconciled to the individual line item amounts presented in the Consolidated Balance Sheet in Note 5.
The following tables present the impact of derivative instruments and their location within the Consolidated Statement of Income for the year ended December 31, 2014 and 2013:
Derivatives in cash flow hedging relationships
	(Gain) loss recognized in AOCI on derivatives (effective portion)								(Gain) loss reclassified from AOCI into income (effective portion)(a)								(Gain) loss recognized in income on derivatives (ineffective portion)(b)
	Year ended								Year ended								Year ended
	December 31,								December 31,								December 31,
(in millions)	2014				2013				2014				2013				2014				2013
Fuel derivative contracts	$	749		*	$	52		*	$	22		*	$	103		*	$	7			$	10
Interest rate derivatives	6			*	(14		)	*	14			*	18			*	(4		)		1
Total	$	755			$	38			$	36			$	121			$	3			$	11
*Net of tax
(a) Amounts related to fuel derivative contracts and interest rate derivatives are included in Fuel and oil and Interest expense, respectively.
(b) Amounts are included in Other (gains) losses, net.
Derivatives not in cash flow hedging relationships
	(Gain) loss
	recognized in income on
	derivatives
	Year ended								Location of (gain) loss
	December 31,								recognized in income
(in millions)	2014				2013				on derivatives
Fuel derivative contracts	$	244			$	(100	)		Other (gains) losses, net
The Company also recorded expense associated with premiums paid for fuel derivative contracts that settled/expired during 2014, 2013, and 2012 of $62 million, $60 million, and $36 million, respectively. These amounts are excluded from the Company’s measurement of effectiveness for related hedges and are included as a component of Other (gains) losses, net, in the Consolidated Statement of Income.
The fair values of the derivative instruments, depending on the type of instrument, were determined by the use of present value methods or option value models with assumptions about commodity prices based on those observed in underlying markets or provided by third parties. Included in the Company’s cumulative net unrealized losses from fuel hedges as of December 31, 2014, recorded in AOCI, were approximately $219 million in unrealized losses, net of taxes, which are expected to be realized in earnings during the twelve months subsequent to December 31, 2014.
Interest rate swaps
The Company is party to certain interest rate swap agreements that are accounted for as either fair value hedges or cash flow hedges, as defined in the applicable accounting guidance for derivative instruments and hedging. Several of the Company's interest rate swap agreements qualify for the “shortcut” method of accounting for hedges, which dictates that the hedges are assumed to be perfectly effective, and, thus, there is no ineffectiveness to be recorded in earnings. For the Company’s interest rate swap agreements that do not qualify for the "shortcut" method of accounting, ineffectiveness is required to be measured at each reporting period. The ineffectiveness associated with all of the Company’s, including AirTran’s, interest rate swap agreements for all periods presented was not material.
The Company has floating-to-fixed interest rate swap agreements associated with its $600 million floating-rate term loan agreement due 2020 and its $332 million term loan agreement due 2019 that are accounted for as cash flow hedges. These interest rate hedges have fixed the interest rate on the $600 million floating-rate term loan agreement at 5.223 percent until maturity, and for the $332 million term loan agreement at 6.315 percent until maturity.
The fair values of the interest rate swap agreements, which are adjusted regularly, have been aggregated by counterparty for classification in the Consolidated Balance Sheet. Agreements totaling an asset of $13 million are fair value hedges and are classified as a component of Other assets. The corresponding adjustment related to the net asset associated with the Company’s fair value hedges is to the carrying value of the long-term debt. Agreements totaling a net liability of $61 million are cash flow hedges and are classified as a component of Other noncurrent liabilities. The corresponding adjustment related to the net liability associated with the Company’s cash flow hedges is to AOCI. See Note 12.
There are also a number of interest rate swap agreements, which convert a portion of AirTran’s floating-rate debt to a fixed-rate basis for the remaining life of the debt, thus reducing the impact of interest rate changes on future interest expense and cash flows. Under these agreements, which expire between 2016 and 2020, it pays fixed rates between 4.35 percent and 6.435 percent and receives either three-month or six-month LIBOR on the notional values. The notional amount of outstanding debt related to interest rate swaps as of December 31, 2014, was $243 million. These interest rate swap arrangements were designated as cash flow hedges as of the acquisition date. The ineffectiveness associated with all of the Company’s interest rate cash flow hedges for all periods presented was not material.
In June 2012, the Company terminated the AirTran floating-to-fixed interest rate swap agreements related to its Floating-rate 737 Aircraft Notes payable through 2020. These swaps were previously designated as cash flow hedges and the gains and/or losses that had previously been deferred in AOCI, which were not material, are being released to expense/income in accordance with the original debt payment schedule. The release of amounts deferred in AOCI related to these interest rate swap agreements was not material during 2014 and is not expected to have a material effect on the Company’s future results of operations.
In December 2012, the Company terminated the fixed-to-floating interest rate swap agreement related to its $100 million 7.375% debentures due 2027. The effect of this termination is such that the interest associated with the debt prospectively reverts back to its original fixed rate. As a result of the approximate $38 million gain realized on this transaction, which will be amortized over the remaining term of the corresponding debentures, and based on projected interest rates at the date of termination, the Company does not believe its future interest expense associated with these debentures will significantly differ from the expense it would have recorded had the debentures remained at floating rates.
During fourth quarter 2014, the Company entered into an interest rate swap agreement related to its $300 million 2.75% Notes due 2019. The primary objective for the Company's use of this interest rate hedge was to reduce the volatility of net interest expense by better matching the repricing of its assets and liabilities. Under this interest rate swap agreement, the Company pays LIBOR plus a margin every six months on the notional amount of the debt, and receives payments based on the fixed stated rate of the notes every six months until the date the notes become due. This interest rate swap agreement qualifies as a fair value hedge, as defined in "Derivatives and Hedging." As a result of the fixed-to-floating interest rate swap agreement in place, the average floating rate recognized during 2014 was approximately 1.23 percent, based on actual and forward rates as of December 31, 2014.
As a result of the fixed-to-floating interest rate swap agreement in place, the average floating rate recognized during 2014 for the Company’s $300 million 5.75% Notes due 2016 was approximately 2.51 percent, based on actual and forward rates as of December 31, 2014.
Credit risk and collateral
Credit exposure related to fuel derivative instruments is represented by the fair value of contracts that are an asset to the Company at the reporting date. At such times, these outstanding instruments expose the Company to credit loss in the event of nonperformance by the counterparties to the agreements. However, the Company has not experienced any significant credit loss as a result of counterparty nonperformance in the past. To manage credit risk, the Company selects and periodically reviews counterparties based on credit ratings, limits its exposure with respect to each counterparty, and monitors the market position of the fuel hedging program and its relative market position with each counterparty. At December 31, 2014, the Company had agreements with all of its active counterparties containing early termination rights and/or bilateral collateral provisions whereby security is required if market risk exposure exceeds a specified threshold amount based on the counterparty credit rating. The Company also had agreements with counterparties in which cash deposits, letters of credit, and/or pledged aircraft are required to be posted whenever the net fair value of derivatives associated with those counterparties exceeds specific thresholds. The following table provides the fair values of fuel derivatives, amounts posted as collateral, and applicable collateral posting threshold amounts as of December 31, 2014, at which such postings are triggered:
	Counterparty (CP)
(in millions)	A				B				C				D				E				F				Other(a)			Total
Fair value of fuel derivatives	$	(333	)		$	(136	)		$	(122	)		$	(219	)		$	(66	)		$	(86	)		$	(39	)	$	(1,001	)
Cash collateral held (by) CP	(50		)		(98		)		(57		)		—				(23		)		(38		)		—			(266		)
Aircraft collateral pledged to CP	(134		)		—				—				—				—				—				—			(134		)
Letters of credit (LC)	(100		)		—				—				(150		)		—				—				—			(250		)
Option to substitute LC for aircraft	<(400)(g)				(100) to (500)(d)				N/A				(150) to (550)(d)				N/A				N/A
Option to substitute LC for cash	(50) to (150)(d)				>(500)				(100) to (150)(e)				(75) to (150) or >(550)(d)				N/A				(f)
If credit rating is investment
grade, fair value of fuel
derivative level at which:
Cash is provided to CP	(50) to (200) or >(600)				(50) to (100) or >(500)				>(75)				(75) to (150) or >(550)				>(50)				>(50)
Cash is received from CP	>50				>150				>175(c)				>200				>30				>(50)
Aircraft or cash can be pledged to	(200) to (600)(d)				(100) to (500)(d)				N/A				(150) to (550)(d)				N/A				N/A
CP as collateral
If credit rating is non-investment
grade, fair value of fuel derivative
level at which:
Cash is provided to CP	(0) to (200) or >(600)				(0) to (100) or >(500)				(b)				(0) to (150) or >(550)				(b)				(b)
Cash is received from CP	(b)				(b)				(b)				(b)				(b)				(b)
Aircraft or cash can be pledged to	(200) to (600)				(100) to (500)				N/A				(150) to (550)				N/A				N/A
CP as collateral
(a) Individual counterparties with fair value of fuel derivatives <$25 million.
(b) Cash collateral is provided at 100 percent of fair value of fuel derivative contracts.
(c) Thresholds may vary based on changes in credit ratings within investment grade.
(d) The Company has the option of providing cash, letters of credit, or pledging aircraft as collateral.
(e) The Company has the option of providing cash or letters of credit as collateral.
(f) The Company has the option to substitute letters of credit for 100 percent of cash collateral requirement.
(g) The Company has the option of providing letters of credit in addition to aircraft collateral if the appraised value of the aircraft does not meet the collateral requirements.

FAIR_VALUE_MEASUREMENTS

FAIR VALUE MEASUREMENTS	12 Months Ended
	Dec. 31, 2014
Fair Value Disclosures [Abstract]
FAIR VALUE MEASUREMENTS	FAIR VALUE MEASUREMENTS
	Accounting standards pertaining to fair value measurements establish a three-tier fair value hierarchy, which prioritizes the inputs used in measuring fair value. These tiers include: Level 1, defined as observable inputs such as quoted prices in active markets; Level 2, defined as inputs other than quoted prices in active markets that are either directly or indirectly observable; and Level 3, defined as unobservable inputs in which little or no market data exists, therefore requiring an entity to develop its own assumptions.
	As of December 31, 2014, the Company held certain items that are required to be measured at fair value on a recurring basis. These included cash equivalents, short-term investments (primarily treasury bills, commercial paper, and certificates of deposit), certain noncurrent investments, interest rate derivative contracts, fuel derivative contracts, and available-for-sale securities. The majority of the Company’s short-term investments consist of instruments classified as Level 1. However, the Company has certificates of deposit, commercial paper, and Eurodollar time deposits that are classified as Level 2, due to the fact that the fair value for these instruments is determined utilizing observable inputs in non-active markets. Noncurrent investments consist of certain auction rate securities, primarily those collateralized by student loan portfolios, which are guaranteed by the U.S. Government. Other available-for-sale securities primarily consist of investments associated with the Company’s excess benefit plan.
	The Company’s fuel and interest rate derivative instruments consist of over-the-counter contracts, which are not traded on a public exchange. Fuel derivative instruments include swaps, as well as different types of option contracts, whereas interest rate derivatives consist solely of swap agreements. See Note 10 for further information on the Company’s derivative instruments and hedging activities. The fair values of swap contracts are determined based on inputs that are readily available in public markets or can be derived from information available in publicly quoted markets. Therefore, the Company has categorized these swap contracts as Level 2. The Company’s Treasury Department, which reports to the Chief Financial Officer, determines the value of option contracts utilizing an option pricing model based on inputs that are either readily available in public markets, can be derived from information available in publicly quoted markets, or are provided by financial institutions that trade these contracts. The option pricing model used by the Company is an industry standard model for valuing options and is the same model used by the broker/dealer community (i.e., the Company’s counterparties). The inputs to this option pricing model are the option strike price, underlying price, risk free rate of interest, time to expiration, and volatility. Because certain inputs used to determine the fair value of option contracts are unobservable (principally implied volatility), the Company has categorized these option contracts as Level 3. Volatility information is obtained from external sources, but is analyzed by the Company for reasonableness and compared to similar information received from other external sources. The fair value of option contracts considers both the intrinsic value and any remaining time value associated with those derivatives that have not yet settled. The Company also considers counterparty credit risk and its own credit risk in its determination of all estimated fair values. To validate the reasonableness of the Company’s option pricing model, on a monthly basis, the Company compares its option valuations to third party valuations. If any significant differences were to be noted, they would be researched in order to determine the reason. However, historically, no significant differences have been noted. The Company has consistently applied these valuation techniques in all periods presented and believes it has obtained the most accurate information available for the types of derivative contracts it holds.
	Included in Other available-for-sale securities are the Company's investments associated with its excess benefit plan which consist of mutual funds that are publicly traded and for which market prices are readily available. This plan is a non-qualified deferred compensation plan designed to hold Employee contributions in excess of limits established by Section 415 of the Internal Revenue Code of 1986, as amended. Payments under this plan are made based on the participant's distribution election and plan balance. Assets related to the funded portion of the deferred compensation plan are held in a rabbi trust, and the Company remains liable to these participants for the unfunded portion of the plan. The Company records changes in the fair value of the asset in the Company's earnings.
	All of the Company’s auction rate security instruments, totaling $27 million (net) at December 31, 2014, are classified as available-for-sale securities and are reflected at their estimated fair value in the Consolidated Balance Sheet. The Company’s Treasury Department determines the estimated fair values of these securities utilizing a discounted cash flow analysis. The Company has performed, and routinely updates, a valuation for each of its auction rate security instruments, considering, among other items, the collateralization underlying the security investments, the expected future cash flows, including the final maturity, associated with the securities, estimates of the next time the security is expected to have a successful auction or return to full par value, forecasted reset rates based on LIBOR or the issuer’s net loan rate, and a counterparty credit spread. To validate the reasonableness of the Company’s discounted cash flow analyses, the Company compares its valuations to third party valuations on a quarterly basis.
	The following tables present the Company’s assets and liabilities that are measured at fair value on a recurring basis at December 31, 2014, and December 31, 2013:
							Fair value measurements at reporting date using:
							Quoted prices in				Significant				Significant
							active markets				other observable				unobservable
							for identical assets				inputs				inputs
	Description		December 31, 2014				(Level 1)				(Level 2)				(Level 3)
	Assets		(in millions)
	Cash equivalents
	Cash equivalents (a)		$	1,110			$	1,110			$	—			$	—
	Commercial paper		70				—				70				—
	Certificates of deposit		4				—				4				—
	Eurodollar Time Deposits		98				—				98				—
	Short-term investments:
	Treasury bills		1,450				1,450				—				—
	Certificates of deposit		256				—				256				—
	Noncurrent investments (b)
	Auction rate securities		27				—				—				27
	Interest rate derivatives (see Note 10)		13				—				13				—
	Fuel derivatives:
	Swap contracts (c)		455				—				455				—
	Option contracts (c)		892				—				—				892
	Other available-for-sale securities		68				63				—				5
	Total assets		$	4,443			$	2,623			$	896			$	924
	Liabilities
	Fuel derivatives:
	Swap contracts (c)		$	(365	)		$	—			$	(365	)		$	—
	Option contracts (c)		(1,983		)		—				—				(1,983		)
	Interest rate derivatives (see Note 10)		(61		)		—				(61		)		—
	Total liabilities		$	(2,409	)		$	—			$	(426	)		$	(1,983	)
	(a) Cash equivalents are primarily composed of money market investments.
	(b) Noncurrent investments are included in Other assets in the Consolidated Balance Sheet.
	(c) In the Consolidated Balance Sheet amounts are presented as a net liability. See Note 10.
							Fair value measurements at reporting date using:
							Quoted prices in				Significant				Significant
							active markets				other observable				unobservable
							for identical assets				inputs				inputs
	Description		December 31, 2013				(Level 1)				(Level 2)				(Level 3)
	Assets		(in millions)
	Cash equivalents
	Cash equivalents (a)		$	992			$	992			$	—			$	—
	Commercial paper		280				—				280				—
	Certificates of deposit		23				—				23				—
	Eurodollar Time Deposits		60				—				60				—
	Short-term investments:
	Treasury bills		1,570				1,570				—				—
	Certificates of deposit		227				—				227				—
	Noncurrent investments (b)
	Auction rate securities		39				—				—				39
	Interest rate derivatives (see Note 10)		20				—				20				—
	Fuel derivatives:
	Swap contracts (c)		16				—				16				—
	Option contracts (c)		458				—				—				458
	Option contracts (d)		9				—				—				9
	Other available-for-sale securities		63				58				—				5
	Total assets		$	3,757			$	2,620			$	626			$	511
	Liabilities
	Fuel derivatives:
	Swap contracts (c)		$	(8	)		$	—			$	(8	)		$	—
Option contracts (c)		(274		)		—				—				(274		)
Swap contracts (d)		(21		)		—				—				(21		)
Interest rate derivatives (see Note 10)		(77		)		—				(77		)		—
Total liabilities		$	(380	)		$	—			$	(85	)		$	(295	)
(a) Cash equivalents are primarily composed of money market investments.
(b) Noncurrent investments are included in Other assets in the Consolidated Balance Sheet.
(c) In the Consolidated Balance Sheet amounts are presented as a net asset. See Note 10.
(d) In the Consolidated Balance Sheet amounts are presented as a net liability. See Note 10.
The Company had no transfers of assets or liabilities between any of the above levels during the years ended December 31, 2014 or 2013. The Company did not have any assets or liabilities measured at fair value on a nonrecurring basis as of December 31, 2014 or 2013. The following tables present the Company’s activity for items measured at fair value on a recurring basis using significant unobservable inputs (Level 3) for 2014 and 2013:
	Fair value measurements using significant
	unobservable inputs (Level 3)
	Fuel				Auction rate				Other
(in millions)	derivatives				securities				securities				Total
Balance at December 31, 2013	$	172			$	39			$	5			$	216
Total gains or (losses) (realized or unrealized)
Included in earnings	(439		)		—				—				(439		)
Included in other comprehensive income	(1,091		)		3				—				(1,088		)
Purchases	403			(a)	—				—				403
Sales	(155		)	(a)	(15		)		—				(170		)
Settlements	19				—				—				19
Balance at December 31, 2014	$	(1,091	)		$	27		(b)	$	5			$	(1,059	)
The amount of total losses for the period	$	(450	)		$	—			$	—			$	(450	)
included in earnings attributable to the
change in unrealized gains or losses relating
to assets still held at December 31, 2014
(a) The purchase and sale of fuel derivatives are recorded gross based on the structure of the derivative instrument and
whether a contract with multiple derivatives is purchased as a single instrument or separate instruments.
(b) Included in Other assets in the Consolidated Balance Sheet.
	Fair value measurements using significant
	unobservable inputs (Level 3)
	Fuel				Auction rate				Other
(in millions)	derivatives				securities				securities				Total
Balance at December 31, 2012	$	219			$	36			$	5			$	260
Total gains or (losses) (realized or unrealized)
Included in earnings	71				—				—				71
Included in other comprehensive income	(107		)		3				—				(104		)
Purchases	357			(a)	—				—				357
Sales	(417		)	(a)	—				—				(417		)
Settlements	49				—				—				49
Balance at December 31, 2013	$	172			$	39		(b)	$	5			$	216
The amount of total gains for the period	$	86			$	—			$	—			$	86
included in earnings attributable to the
change in unrealized gains or losses relating
to assets still held at December 31, 2013
(a) The purchase and sale of fuel derivatives are recorded gross based on the structure of the derivative instrument and
whether a contract with multiple derivatives is purchased as a single instrument or separate instruments.
(b) Included in Other assets in the Consolidated Balance Sheet.
The significant unobservable input used in the fair value measurement of the Company’s derivative option contracts is implied volatility. Holding other inputs constant, a significant increase (decrease) in implied volatility would result in a significantly higher (lower) fair value measurement, respectively, for the Company’s derivative option contracts. The significant unobservable inputs used in the fair value measurement of the Company’s auction rate securities are time to principal recovery, an illiquidity premium, and counterparty credit spread. Holding other inputs constant, a significant increase (decrease) in such unobservable inputs would result in a significantly lower (higher) fair value measurement, respectively.
The following table presents a range of the unobservable inputs utilized in the fair value measurements of the Company’s assets and liabilities classified as Level 3 at December 31, 2014:
Quantitative information about Level 3 fair value measurements
	Valuation technique	Unobservable input	Period (by year)	Range
Fuel derivatives	Option model	Implied volatility	2015	23-47%
			2016	24-36%
			2017	19-30%
			2018	25-27%
Auction rate securities	Discounted cash flow	Time to principal recovery		8 years
		Illiquidity premium		3%
		Counterparty credit spread		1-2%
The carrying amounts and estimated fair values of the Company’s long-term debt (including current maturities), as well as the applicable fair value hierarchy tier, at December 31, 2014, are presented in the table below. The fair values of the Company’s publicly held long-term debt are determined based on inputs that are readily available in public markets or can be derived from information available in publicly quoted markets; therefore, the Company has categorized these agreements as Level 2. Six of the Company’s debt agreements are not publicly held. The Company has determined the estimated fair value of this debt to be Level 3, as certain inputs used to determine the fair value of these agreements are unobservable. The Company utilizes indicative pricing from counterparties and a discounted cash flow method to estimate the fair value of the Level 3 items.
(in millions)	Carrying value			Estimated fair value			Fair value level hierarchy
5.75% Notes due 2016	313			335			Level 2
5.25% Convertible Senior Notes due 2016	113			318			Level 2
5.125% Notes due 2017	316			338			Level 2
French Credit Agreements due 2018 - 1.06%	36			36			Level 3
Fixed-rate 737 Aircraft Notes payable through 2018 - 7.02%	24			25			Level 3
2.75% Notes due 2019	300			304			Level 2
Term Loan Agreement due 2019 - 6.315%	178			178			Level 3
Term Loan Agreement due 2019 - 6.84%	73			79			Level 3
Term Loan Agreement due 2020 - 5.223%	372			367			Level 3
Floating-rate 737 Aircraft Notes payable through 2020	300			293			Level 3
Pass Through Certificates due 2022 - 6.24%	355			410			Level 2
7.375% Debentures due 2027	134			160			Level 2

ACCUMULATED_OTHER_COMPREHENSIV

ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS)	12 Months Ended
	Dec. 31, 2014
Equity [Abstract]
ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS)	ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS)
	Comprehensive income includes changes in the fair value of certain financial derivative instruments that qualify for hedge accounting, unrealized gains and losses on certain investments, and actuarial gains/losses arising from the Company’s postretirement benefit obligation.  A rollforward of the amounts included in AOCI, net of taxes, is shown below for 2014 and 2013:
	(in millions)	Fuel derivatives			Interest rate derivatives			Defined benefit plan items			Other			Deferred tax impact		Accumulated other
																comprehensive income (loss)
	Balance at December 31, 2012	$	(103	)	$	(108	)	$	26		$	(8	)	$	74	$	(119	)
	changes in fair value	(82		)	22			39			16			—		(5		)
	Reclassification to earnings	165			28			—			—			-72		121
	Balance at December 31, 2013	$	(20	)	$	(58	)	$	65		$	8		$	2	$	(3	)
	changes in fair value	(1,191		)	(10		)	(24		)	—			454		(771		)
	Reclassification to earnings	34			23			—			—			-21		36
	Balance at December 31, 2014	$	(1,177	)	$	(45	)	$	41		$	8		$	435	$	(738	)
	The following table illustrates the significant amounts reclassified out of each component of AOCI for the year ended December 31, 2014:
	Year ended December 31, 2014
	(in millions)		Amounts reclassified from AOCI			Affected line item in the Consolidated Statement of Comprehensive Income
	AOCI components
	Unrealized gain on fuel derivative instruments		$	34		Fuel and oil expense
			12			Less: Tax expense
			$	22		Net of tax
	Unrealized gain on interest rate derivative instruments		$	23		Interest expense
			9			Less: Tax expense
			$	14		Net of tax
	Total reclassifications for the period		$	36		Net of tax

EMPLOYEE_RETIREMENT_PLANS

EMPLOYEE RETIREMENT PLANS	12 Months Ended
	Dec. 31, 2014
Compensation and Retirement Disclosure [Abstract]
EMPLOYEE RETIREMENT PLANS	EMPLOYEE RETIREMENT PLANS
	Defined contribution plans
	Southwest has defined contribution plans covering substantially all of its Employees. Contributions under all defined contribution plans are primarily based on Employee compensation and performance of the Company. The Company sponsors Employee savings plans under section 401(k) of the Internal Revenue Code, which include Company matching contributions. In addition, the Southwest Airlines Co. ProfitSharing Plan (ProfitSharing Plan) is a defined contribution plan to which the Company may contribute a percentage of its eligible pre-tax profits, as defined, on an annual basis. No Employee contributions to the ProfitSharing Plan are allowed. AirTran Employees became eligible to participate in Southwest’s ProfitSharing Plan beginning January 1, 2012.
	Company contributions to all defined contribution plans expensed in 2014, 2013, and 2012, reflected as a component of Salaries, wages, and benefits, were $644 million, $497 million, and $370 million, respectively.
	Postretirement benefit plans
	The Company provides postretirement benefits to qualified retirees in the form of medical and dental coverage. Employees must meet minimum levels of service and age requirements as set forth by the Company, or as specified in collective bargaining agreements with specific workgroups. Employees meeting these requirements, as defined, may use accrued unused sick time to pay for medical and dental premiums from the age of retirement until age 65.
	The following table shows the change in the accumulated postretirement benefit obligation (APBO) for the years ended December 31, 2014 and 2013:
	(in millions)		2014				2013
	APBO at beginning of period		$	138			$	148
	Service cost		10				30
	Interest cost		7				4
	Benefits paid		(4		)		(3		)
	Actuarial (gain)/loss		21				(41		)
	Settlements		$	(3	)		$	—
	APBO at end of period		$	169			$	138
	All plans are unfunded, and benefits are paid as they become due. Estimated future benefit payments expected to be paid are $5 million in 2015, $6 million in 2016, $7 million in 2017, $7 million in 2018, $8 million in 2019, and $55 million for the next five years thereafter.
	The funded status (the difference between the fair value of plan assets and the projected benefit obligations) of the Company’s consolidated benefit plans are recognized in the Consolidated Balance Sheet, with a corresponding adjustment to AOCI. The following table reconciles the funded status of the plans to the accrued postretirement benefit cost recognized in Other non-current liabilities on the Company’s Consolidated Balance Sheet at December 31, 2014 and 2013.
	(in millions)		2014				2013
	Funded status		$	(169	)		$	(138	)
	Unrecognized net actuarial gain		(53		)		(80		)
	Unrecognized prior service cost		12				15
	Accumulated other comprehensive income		41				65
	Cost recognized on Consolidated Balance Sheet		$	(169	)		$	(138	)
	The consolidated periodic postretirement benefit cost for the years ended December 31, 2014, 2013, and 2012, included the following:
	(in millions)		2014				2013				2012
	Service cost		$	10			$	30			$	20
	Interest cost		7				4				4
	Amortization of prior service cost		3				3				—
	Recognized actuarial gain		(4		)		(4		)		(5		)
	Settlements		$	(1	)		$	—			$	—
	Net periodic postretirement benefit cost		$	15			$	33			$	19
	Unrecognized prior service cost is expensed using a straight-line amortization of the cost over the average future service of Employees expected to receive benefits under the plans. Actuarial gains are amortized utilizing the minimum amortization method. The following actuarial assumptions were used to account for the Company’s postretirement benefit plans at December 31, 2014, 2013, and 2012:
			2014			2013			2012
	Weighted-average discount rate		4.1	%		5.05	%		2.9	%
	Assumed healthcare cost trend rate (1)		6.88	%		7.5	%		8	%
	-1	The assumed healthcare cost trend rate is assumed to remain at 6.88% for 2015, then decline gradually to 5.00% by 2025 and remain level thereafter.
	The assumed healthcare cost trend rates have a significant effect on the amounts reported for the consolidated postretirement plans. A one percent change in all healthcare cost trend rates used in measuring the APBO at December 31, 2014, would have the following effects:
	(in millions)		1% increase				1% decrease
	Increase (decrease) in total service and interest costs		$	3			$	(2	)
	Increase (decrease) in the APBO		$	24			$	(20	)
	The selection of a discount rate is made annually and is selected by the Company based upon comparison of the expected future cash flows associated with the Company’s future payments under its consolidated postretirement obligations to a yield curve created using high quality bonds that closely match those expected future cash flows. This rate decreased during 2014 due to market conditions. The assumed healthcare trend rate is also reviewed at least annually and is determined based upon both historical experience with the Company’s healthcare benefits paid and expectations of how those trends may or may not change in future years.

INCOME_TAXES

INCOME TAXES	12 Months Ended
	Dec. 31, 2014
Income Tax Disclosure [Abstract]
INCOME TAXES	INCOME TAXES
	Deferred income taxes reflect the net tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. The components of deferred tax assets and liabilities at December 31, 2014 and 2013, are as follows:
	(in millions)	2014			2013
	DEFERRED TAX LIABILITIES:
	Accelerated depreciation	$	4,277		$	4,069
	Fuel derivative instruments	—			36
	Other	51			84
	Total deferred tax liabilities	4,328			4,189
	DEFERRED TAX ASSETS:
	Fuel derivative instruments	521			8
	Deferred gains from sale and leaseback of aircraft	20			24
	Capital and operating leases	125			163
	Construction obligation	209			168
	Accrued engine maintenance	83			90
	Accrued employee benefits	334			307
	State taxes	65			74
	Business partner income	90			457
	Net operating losses and credit carryforwards	3			14
	Other	96			118
	Total deferred tax assets	1,546			1,423
	Net deferred tax liability	$	2,782		$	2,766
	The provision for income taxes is composed of the following:
	(in millions)	2014			2013			2012
	CURRENT:
	Federal	$	203		$	355		$	(45	)
	State	29			44			12
	Total current	232			399			(33		)
	DEFERRED:
	Federal	421			62			287
	State	27			(6		)	10
	Total deferred	448			56			297
		$	680		$	455		$	264
	The effective tax rate on income before income taxes differed from the federal income tax statutory rate for the following reasons:
	(in millions)	2014			2013			2012
	Tax at statutory U.S. tax rates	$	636		$	423		$	240
	Nondeductible items	9			10			10
	State income taxes, net of federal benefit	37			25			14
	Other, net	(2		)	(3		)	—
	Total income tax provision	$	680		$	455		$	264
	During 2014, the Company continued to maintain and did not adjust, a $5 million liability for unrecognized tax benefits, the majority of which related to AirTran’s tax positions in prior years.
	The only periods subject to examination for the Company’s federal tax return are the 2013 and 2014 tax years.

QUARTERLY_FINANCIAL_DATA

QUARTERLY FINANCIAL DATA	12 Months Ended
	Dec. 31, 2014
Quarterly Financial Data [Abstract]
QUARTERLY FINANCIAL DATA	QUARTERLY FINANCIAL DATA
	(unaudited)
		Three months ended
	(in millions except per share amounts)	March 31		June 30		Sept. 30		Dec. 31
	2014
	Operating revenues	$	4,166	$	5,011	$	4,800	$	4,628	(a)
	Operating income	215		775		614		621
	Income before income taxes	244		746		525		302
	Net income	152		465		329		190
	Net income per share, basic	0.22		0.67		0.48		0.28		(a)
	Net income per share, diluted	0.22		0.67		0.48		0.28		(a)
		31-Mar		30-Jun		Sept. 30		Dec. 31
	2013
	Operating revenues	$	4,084	$	4,643	$	4,545	$	4,428
	Operating income	70		433		390		386
	Income (loss) before income taxes	94		363		419		334
	Net income (loss)	59		224		259		212
	Net income (loss) per share, basic	0.08		0.31		0.37		0.3
	Net income (loss) per share, diluted	0.08		0.31		0.37		0.3
	(a) Includes a change in estimate, recorded on a prospective basis, effective October 1, 2014, which increased Passenger revenues by approximately $55 million and increased both Basic and Diluted net income per share by $.04. See Note 1 for further detail.

Recovered_Sheet1

Summary of Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2014

Accounting Policies [Abstract]

Basis of Presentation

Basis of Presentation

Southwest Airlines Co. (the “Company”) operates Southwest Airlines, a major domestic airline. The Consolidated Financial Statements include the accounts of the Company and its wholly owned subsidiaries, which include AirTran Holdings, LLC. On May 2, 2011 (the “acquisition date”), the Company acquired all of the outstanding equity of AirTran Holdings, Inc. (“AirTran Holdings”), the former parent company of AirTran Airways, Inc. (“AirTran Airways”). Throughout these Notes, the Company makes reference to AirTran, which is meant to be inclusive of the following: (i) for periods prior to the acquisition date, AirTran Holdings and its subsidiaries, including, among others, AirTran Airways; and (ii) for periods on and after the acquisition date, AirTran Holdings, LLC, the successor to AirTran Holdings, and its subsidiaries, including among others, AirTran Airways. The accompanying Consolidated Financial Statements include the results of operations and cash flows for all periods presented and all significant inter-entity balances and transactions have been eliminated. The preparation of financial statements in conformity with generally accepted accounting principles in the United States (GAAP) requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. Actual results could differ from these estimates.

Certain prior period amounts have been reclassified to conform to the current presentation. In the Consolidated Statement of Cash Flows for the year ended December 31, 2013, the Company has reclassified $14 million from Capital expenditures to Assets constructed for others. See Note 4 for further information.

Cash and cash equivalents

Cash and cash equivalents

Cash in excess of that necessary for operating requirements is invested in short-term, highly liquid, income-producing investments. Investments with original maturities of three months or less when purchased are classified as cash and cash equivalents, which primarily consist of certificates of deposit, money market funds, and investment grade commercial paper issued by major corporations and financial institutions. Cash and cash equivalents are stated at cost, which approximates fair value.

As of December 31, 2014, $266 million in cash collateral deposits were provided by the Company to its fuel hedge counterparties and no cash collateral deposits were held by or provided by the Company to its interest rate hedge counterparties. As of December 31, 2013, the Company had no cash collateral deposits held by or provided by the Company to its fuel hedge counterparties and the Company had provided cash collateral deposits totaling $32 million to its interest rate hedge counterparties. Cash collateral amounts provided or held associated with fuel and interest rate derivative instruments are not restricted in any way and earn interest income at an agreed upon rate that approximates the rates earned on short-term securities issued by the U.S. Government. Depending on the fair value of the Company’s fuel and interest rate derivative instruments, the amounts of collateral deposits held or provided at any point in time can fluctuate significantly. See Note 10 for further information on these collateral deposits and fuel derivative instruments.

Short-term and noncurrent investments

Short-term and noncurrent investments

Short-term investments consist of investments with original maturities of greater than three months but less than twelve months when purchased. These are primarily short-term securities issued by the U.S. Government and certificates of deposit issued by domestic banks. All of these investments are classified as available-for-sale securities and are stated at fair value, which approximates cost. For all short-term investments, at each reset period or upon reinvestment, the Company accounts for the transaction as Proceeds from sales of short-term investments for the security relinquished, and Purchases of short-investments for the security purchased, in the accompanying Consolidated Statement of Cash Flows. Unrealized gains and losses, net of tax, if any, are recognized in Accumulated other comprehensive income (loss) (“AOCI”) in the accompanying Consolidated Balance Sheet. Realized net gains and losses on specific investments, if any, are reflected in Interest income in the accompanying Consolidated Statement of Income. Both unrealized and realized gains and/or losses associated with investments were immaterial for all years presented.

Noncurrent investments consist of investments with maturities of greater than twelve months. At December 31, 2014, these primarily consisted of the Company’s auction rate security instruments that it expects will not be redeemed during 2015. See Note 11 for further information. Noncurrent investments are included as a component of Other assets in the Consolidated Balance Sheet.

Accounts and other receivables

Accounts and other receivables

Accounts and other receivables are carried at cost. They primarily consist of amounts due from credit card companies associated with sales of tickets for future travel, amounts due from business partners in the Company’s frequent flyer program, and amounts due from counterparties associated with fuel derivative instruments that have settled. The allowance for doubtful accounts was immaterial at December 31, 2014 and 2013. In addition, the provision for doubtful accounts and write-offs for 2014 and 2013 were each immaterial.

Inventories

Inventories

Inventories consist primarily of aircraft fuel, flight equipment expendable parts, materials, and supplies. All of these items are carried at average cost, less an allowance for obsolescence. These items are generally charged to expense when issued for use. The reserve for obsolescence was $46 million and $36 million at December 31, 2014, and 2013, respectively. In addition, the Company’s provision for obsolescence and write-offs for 2014, 2013, and 2012 were each immaterial.

Property and equipment

Property and equipment

Property and equipment is stated at cost. Capital expenditures includes payments made for aircraft, other flight equipment, purchase deposits related to future aircraft deliveries, and ground and other property and equipment. Depreciation is provided by the straight-line method to estimated residual values over periods generally ranging from 23 to 25 years for flight equipment and 5 to 30 years for ground property and equipment once the asset is placed in service. Residual values estimated for aircraft generally range from 2 to 20 percent and for ground property and equipment generally range from 0 to 10 percent. Property under capital leases and related obligations are initially recorded at an amount equal to the present value of future minimum lease payments computed on the basis of the Company’s incremental borrowing rate or, when known, the interest rate implicit in the lease. Amortization of property under capital leases is on a straight-line basis over the lease term and is included in Depreciation and amortization expense. Leasehold improvements generally are amortized on a straight-line basis over the shorter of the estimated useful life of the improvement or the remaining term of the lease. Assets constructed for others primarily consists of airport improvement projects, once placed into service, in which the Company is considered the accounting owner of the facilities, and such assets are amortized to estimated residual value over the term of the Company's lease or the expected life of the asset. See Note 4 for further information.

The Company evaluates its long-lived assets used in operations for impairment when events and circumstances indicate that the undiscounted cash flows to be generated by that asset are less than the carrying amounts of the asset and may not be recoverable. Factors that would indicate potential impairment include, but are not limited to, significant decreases in the market value of the long-lived asset(s), a significant change in the long-lived asset’s physical condition, and operating or cash flow losses associated with the use of the long-lived asset. If an asset is deemed to be impaired, an impairment loss is recorded for the excess of the asset book value in relation to its estimated fair value.

During first quarter 2012 the Company changed the estimated retirement dates of several 737-300 and 737-500 aircraft based on revisions in the Company’s fleet plan. This change, which was accounted for on a prospective basis, resulted in an acceleration of depreciation expense, since the majority of these aircraft had previously been expected to retire in periods beyond 2012, but were subsequently expected to be retired during 2012. The impact of this change on the year ended December 31, 2012 was an increase to Depreciation expense of $12 million. Excluding the impact of Profitsharing and income taxes, the change resulted a $6 million decrease to Net income and a $0.01 decrease to Basic and Diluted Net income per share for the year ended December 31, 2012.

During third quarter 2012 the Company changed the estimated residual values of its entire fleet of owned 737-300 and 737-500 aircraft. This change was based on an agreement entered into during July 2012, pursuant to which the Company will lease or sublease certain aircraft to Delta Air Lines, Inc., and the resulting impact this transaction will have on how the Company manages the ultimate retirement of its owned 737-300 and 737-500 aircraft. See Note 7 for further information on the lease/sublease transaction. Based on the expected retirement dates and then current and expected future market conditions related to its owned 737-300 and 737-500 aircraft, the Company reduced the residual values of these aircraft from approximately ten percent of original cost to approximately two percent of original cost. As this reduction in residual value was considered a change in estimate, it was accounted for on a prospective basis, and thus the Company will record additional depreciation expense over the remainder of the useful lives for each aircraft. The impact of this change on the year ended December 31, 2012 was an increase to Depreciation expense of $34 million. Excluding the impact of Profitsharing and income taxes, the change resulted an $18 million decrease to Net income and a $0.02 decrease to Basic and Diluted Net income per share for the year ended December 31, 2012.

Aircraft and engine maintenance

Aircraft and engine maintenance

The cost of scheduled inspections and repairs and routine maintenance costs for all aircraft and engines are charged to Maintenance materials and repairs expense as incurred. The Company also has “power-by-the-hour” agreements related to certain of its aircraft engines with external service providers. Under these agreements, which the Company has determined effectively transfers the risk and creates an obligation associated with the maintenance on such engines to the counterparty, expense is recorded commensurate with each hour flown on an engine. In situations where the payments to the counterparty do not sufficiently match the level of services received during the period, expense is recorded on a straight-line basis over the term of the agreement based on our best estimate of expected future aircraft utilization. For its engine maintenance contracts that do not transfer risk to the service provider, the Company records expense on a time and materials basis when an engine repair event takes place. Modifications that significantly enhance the operating performance or extend the useful lives of aircraft or engines are capitalized and amortized over the remaining life of the asset.

Goodwill and intangible assets

Goodwill and intangible assets

The Company applies a fair value based impairment test to the carrying value of goodwill and indefinite-lived intangible assets on an annual basis (as of October 1), or more frequently if certain events or circumstances indicate that an impairment loss may have been incurred. The FASB standard “Testing Indefinite-Lived Intangible Assets for Impairment” gives companies the option to perform a qualitative assessment to determine whether it is more likely than not that an indefinite-lived intangible asset is impaired rather than calculating the fair value of the indefinite-lived intangible asset. The Company adopted this standard and has applied the provisions to its annual indefinite-lived intangible asset impairment test for 2014.

The Company first utilizes a qualitative approach and analyzes various factors to determine if events and circumstances have affected the fair value of the goodwill and indefinite-lived intangible assets. If the Company determines it is more likely than not that the asset value may be impaired, the Company then uses the quantitative approach to assess the asset’s fair value and amount of impairment. As a result of the Company’s qualitative analyses performed during 2014 the Company concluded it was more likely than not that the fair values of its Goodwill and Indefinite-lived intangible assets was greater than the carrying value and; therefore, a quantitative assessment was not necessary.

Intangible assets primarily consist of acquired leasehold rights to certain airport owned gates at Chicago’s Midway International Airport, take-off and landing slots at certain domestic slot-controlled airports, and certain intangible assets recognized from the AirTran acquisition. The following table is a summary of the Company’s intangible assets, which are included as a component of Other assets in the Company's Consolidated Balance Sheet, as of December 31, 2014 and 2013:

Year ended December 31, 2014

Year ended December 31, 2013

(in millions)

Weighted-average useful life (in years)

Gross carrying

Accumulated

Gross carrying amount

Accumulated Amortization

amount

amortization

Customer relationships/marketing agreements

9

$

38

$

26

$

39

$

23

Trademarks/trade names

6

36

30

36

25

Owned domestic slots

Indefinite

303

n/a

93

n/a

Leased domestic slots (a)

39

19

5

19

4

Non-compete agreements

2

5

5

5

5

Gate leasehold rights

19

60

32

60

29

Total

15

$

461

$

98

$

252

$

86

(a) Useful life of leased slots is based on the stated lease term.

During fourth quarter 2013, following the Company’s acquisition of additional slots at New York’s LaGuardia Airport, the Company made the determination that all of its owned domestic slots should be assigned an indefinite life and would thus not be subject to further amortization, including those that are owned but leased to other carriers. In addition, during first quarter 2014, the Company acquired additional slots at Washington’s Ronald Reagan National Airport which were also assigned an indefinite life. Among other factors, the determination that all of the Company's owned domestic slots should be assigned an indefinite life was due to the Company’s reassessment of the current size and importance of its operations at New York’s LaGuardia Airport and Washington’s Ronald Reagan National Airport versus when the Company first began service to these airports in recent years. The impact of this prospective change in accounting estimate is immaterial.

The aggregate amortization expense for 2014, 2013, and 2012 was $13 million, $19 million, and $25 million, respectively. Estimated aggregate amortization expense for the five succeeding years and thereafter is as follows: 2015 – $11 million, 2016 – $8 million, 2017 – $5 million, 2018 – $5 million, 2019 – $4 million, and thereafter – $27 million.

Revenue recognition

Revenue recognition

Tickets sold are initially deferred as Air traffic liability. Passenger revenue is recognized when transportation is provided. Air traffic liability primarily represents tickets sold for future travel dates and estimated refunds and exchanges of tickets sold for past travel dates. The majority of the Company’s tickets sold are nonrefundable. Refundable tickets that are sold but not flown on the travel date can be reused for another flight, up to a year from the date of sale, or refunded. A small percentage of tickets (or partial tickets) expire unused. The Company estimates the amount of tickets that expire unused and recognizes such amounts in Passenger revenue using the redemption method based on scheduled flight date. Prior to September 13, 2013, funds associated with tickets in which a passenger did not show up for a flight without canceling were able to be reused on another flight for up to twelve months. On September 13, 2013, Southwest implemented a No Show policy that applies to nonrefundable fares that are not canceled or changed by a Customer at least ten minutes prior to a flight's scheduled departure. Based on the Company's revenue recognition policy, revenue is now recorded at the flight date for a Customer who does not change his/her itinerary and loses his/her funds. Amounts collected from passengers for ancillary services such as baggage and other fees are generally recognized as Other revenue when the service is provided, which is typically the flight date.

The Company's policy is to record revenue for the estimated spoilage of tickets (including partial tickets) once the flight date has passed, under the redemption method. Initial spoilage estimates are routinely adjusted and ultimately finalized once the tickets expire, which is typically twelve months after the original purchase date. Spoilage estimates are based on the Customers' historical travel behavior as well as assumptions about the Customers' future travel behavior. Assumptions used to generate spoilage estimates can be impacted by several factors including, but not limited to: fare increases, fare sales, changes to the Company's ticketing policies, changes to the Company’s refund, exchange and unused funds policies, or economic factors.

The Company is also required to collect certain taxes and fees from Customers on behalf of government agencies and remit these back to the applicable governmental entity on a periodic basis. These taxes and fees include U.S. federal transportation taxes, federal security charges, and airport passenger facility charges. These items are collected from Customers at the time they purchase their tickets, but are not included in Passenger revenue. The Company records a liability upon collection from the Customer and relieves the liability when payments are remitted to the applicable governmental agency.

Frequent flyer program

Frequent flyer program

The Company records a liability for the estimated incremental cost of providing free travel under its frequent flyer program for all amounts earned from flight activity that are expected to be redeemed for future travel. The estimated incremental cost includes direct passenger costs such as fuel, food, and other operational costs, but does not include any contribution to fixed overhead costs or profit.

Southwest also sells frequent flyer points and related services to companies participating in its frequent flyer program. Funds received from the sale of these points are accounted for using the residual method. Under this method, the Company determined the portion of funds received that relate to free travel were currently estimated to be 100 percent of the amount received under the Company's Rapid Reward program as of December 31, 2014. These amounts are deferred and recognized as Passenger revenue when the ultimate free travel awards are flown. For all points sold to business partners that are expected to expire unused, the Company recognizes spoilage in accordance with the redemption method. The Company's consolidated liability associated with the sale of frequent flyer points and/or flight credits, was approximately $1.3 billion and $1.1 billion as of December 31, 2014, and 2013, respectively. This liability is included as part of Air Traffic liability in the Company’s Consolidated Balance Sheet.

During fourth quarter 2014, the Company increased the amount of spoilage recorded associated with frequent flyer points sold to business partners as a result of continued monitoring of Member redemption activity and behavior under its Rapid Rewards program. Based on a sufficient amount of historical data and Member attributes observed since the new program was launched in 2011, the Company developed a predictive statistical model to analyze the amount of spoilage expected. In estimating spoilage, the Company takes into account the Member’s past behavior, as well as several factors that are expected to be indicative of the likelihood of future point redemption. These factors include, but are not limited to, tenure with program, points accrued in the program, and whether or not the customer has a co-branded credit card. This change in estimate, which was recorded on a prospective basis, effective October 1, 2014, increased Passenger revenues by approximately $55 million for the quarter and the year ended December 31, 2014. After consideration of profitsharing and taxes, the impact of this change to net income was an increase of $29 million, or $.04 per Basic and Diluted share, for the year ended December 31, 2014. The higher spoilage rate is expected to continue in 2015; however, the precise revenue impact will not be determinable until the actual number of point redemptions for the period is known.

Advertising

Advertising

Advertising costs are charged to expense as incurred. Advertising and promotions expense for the years ended December 31, 2014, 2013, and 2012 was $207 million, $208 million, and $223 million, respectively, and is included as a component of Other operating expense in the accompanying Consolidated Statement of Income.

Share-based Employee compensation

Share-based Employee compensation

The Company has share-based compensation plans covering certain Employees, including plans covering the Company’s Board of Directors. The Company accounts for share-based compensation based on its grant date fair value. See Note 9 for further information.

The fair value of RSUs and PBRSUs is based on the closing price of the Company’s common stock on the date of grant. Outstanding RSUs vest over three years, subject generally to the individual’s continued employment or service. The PBRSUs vest on May 14, 2017, subject to the Company’s performance with respect to a three-year simple average of Return on Invested Capital, before taxes and excluding special items ("ROIC"), for the period beginning on January 1, 2014 and ending on December 31, 2016, and the individual’s continued employment or service. The number of PBRSUs vesting on the vesting date will be interpolated based on the average ROIC for the defined performance period, and ranges from zero PBRSUs at an average ROIC of 12 percent or lower to 200 percent of granted PBRSUs at an average ROIC of 20 percent or higher. The Company recognizes all expense on a straight-line basis over the vesting period, with any changes in expense due to the number of PBRSUs expected to vest being modified on a prospective basis.

The Company accounts for share-based compensation utilizing fair value.

A portion of the Company’s granted options qualify as incentive stock options for income tax purposes. As such, a tax benefit is not recorded at the time the compensation cost related to the options is recorded for book purposes due to the fact that an incentive stock option does not ordinarily result in a tax benefit unless there is a disqualifying disposition. Grants of non-qualified stock options result in the creation of a deferred tax asset, which is a temporary difference, until the time that the option is exercised. Due to the treatment of incentive stock options for tax purposes, the Company’s effective tax rate from year to year is subject to variability.

The Black-Scholes option valuation model was developed for use in estimating the fair value of short-term traded options that have no vesting restrictions and are fully transferable. In addition, option valuation models require the input of subjective assumptions including expected stock price volatility. The Company estimates expected stock price volatility via observations of both historical volatility trends as well as implied future volatility observations as determined by independent third parties.

Fair Value of Financial Instruments

Financial derivative instruments

The Company accounts for financial derivative instruments at fair value and applies hedge accounting rules where appropriate. The Company utilizes various derivative instruments, including jet fuel, crude oil, unleaded gasoline, and heating oil-based derivatives, to attempt to reduce the risk of its exposure to jet fuel price increases. These instruments consist primarily of purchased call options, collar structures, call spreads, put spreads, and fixed price swap agreements, and upon proper qualification are accounted for as cash-flow hedges. The Company also has interest rate swap agreements to convert a portion of its fixed-rate debt to floating rates and has swap agreements that convert certain floating-rate debt to a fixed-rate. These interest rate hedges are appropriately designated as either fair value hedges or as cash flow hedges.

Since the majority of the Company’s financial derivative instruments are not traded on a market exchange, the Company estimates their fair values. Depending on the type of instrument, the values are determined by the use of present value methods or option value models with assumptions about commodity prices based on those observed in underlying markets. Also, since there is not a reliable forward market for jet fuel, the Company must estimate the future prices of jet fuel in order to measure the effectiveness of the hedging instruments in offsetting changes to those prices. Forward jet fuel prices are estimated through utilization of a statistical-based regression equation with data from market forward prices of like commodities. This equation is then adjusted for certain items, such as transportation costs, that are stated in the Company’s fuel purchasing contracts with its vendors.

For the effective portion of settled fuel hedges, the Company records the associated gains or losses as a component of Fuel and oil expense in the Consolidated Statement of Income. For amounts representing ineffectiveness, as defined, or changes in fair value of derivative instruments for which hedge accounting is not applied, the Company records any gains or losses as a component of Other (gains) losses, net, in the Consolidated Statement of Income. Amounts that are paid or received in connection with the purchase or sale of financial derivative instruments (i.e., premium costs of option contracts) are classified as a component of Other (gains) losses, net, in the Consolidated Statement of Income in the period in which the instrument settles or expires. All cash flows associated with purchasing and selling derivatives are classified as operating cash flows in the Consolidated Statement of Cash Flows, within Changes in certain assets and liabilities. See Note 10 for further information on hedge accounting and financial derivative instruments.

The Company classifies its cash collateral provided to or held from counterparties in a “net” presentation on the Consolidated Balance Sheet against the fair value of the derivative positions with those counterparties. See Note 10 for further information.

Accounting standards pertaining to fair value measurements establish a three-tier fair value hierarchy, which prioritizes the inputs used in measuring fair value. These tiers include: Level 1, defined as observable inputs such as quoted prices in active markets; Level 2, defined as inputs other than quoted prices in active markets that are either directly or indirectly observable; and Level 3, defined as unobservable inputs in which little or no market data exists, therefore requiring an entity to develop its own assumptions.

As of December 31, 2014, the Company held certain items that are required to be measured at fair value on a recurring basis. These included cash equivalents, short-term investments (primarily treasury bills, commercial paper, and certificates of deposit), certain noncurrent investments, interest rate derivative contracts, fuel derivative contracts, and available-for-sale securities. The majority of the Company’s short-term investments consist of instruments classified as Level 1. However, the Company has certificates of deposit, commercial paper, and Eurodollar time deposits that are classified as Level 2, due to the fact that the fair value for these instruments is determined utilizing observable inputs in non-active markets. Noncurrent investments consist of certain auction rate securities, primarily those collateralized by student loan portfolios, which are guaranteed by the U.S. Government. Other available-for-sale securities primarily consist of investments associated with the Company’s excess benefit plan.

The Company’s fuel and interest rate derivative instruments consist of over-the-counter contracts, which are not traded on a public exchange. Fuel derivative instruments include swaps, as well as different types of option contracts, whereas interest rate derivatives consist solely of swap agreements. See Note 10 for further information on the Company’s derivative instruments and hedging activities. The fair values of swap contracts are determined based on inputs that are readily available in public markets or can be derived from information available in publicly quoted markets. Therefore, the Company has categorized these swap contracts as Level 2. The Company’s Treasury Department, which reports to the Chief Financial Officer, determines the value of option contracts utilizing an option pricing model based on inputs that are either readily available in public markets, can be derived from information available in publicly quoted markets, or are provided by financial institutions that trade these contracts. The option pricing model used by the Company is an industry standard model for valuing options and is the same model used by the broker/dealer community (i.e., the Company’s counterparties). The inputs to this option pricing model are the option strike price, underlying price, risk free rate of interest, time to expiration, and volatility. Because certain inputs used to determine the fair value of option contracts are unobservable (principally implied volatility), the Company has categorized these option contracts as Level 3. Volatility information is obtained from external sources, but is analyzed by the Company for reasonableness and compared to similar information received from other external sources. The fair value of option contracts considers both the intrinsic value and any remaining time value associated with those derivatives that have not yet settled. The Company also considers counterparty credit risk and its own credit risk in its determination of all estimated fair values. To validate the reasonableness of the Company’s option pricing model, on a monthly basis, the Company compares its option valuations to third party valuations. If any significant differences were to be noted, they would be researched in order to determine the reason. However, historically, no significant differences have been noted. The Company has consistently applied these valuation techniques in all periods presented and believes it has obtained the most accurate information available for the types of derivative contracts it holds.

Software capitalization

Software capitalization

The Company capitalizes certain internal and external costs related to the acquisition and development of internal use software during the application development stages of projects. The Company amortizes these costs using the straight-line method over the estimated useful life of the software, which typically ranges from five to fifteen years. Costs incurred during the preliminary project or the post-implementation/operation stages of the project are expensed as incurred. Capitalized computer software, included as a component of Ground property and equipment in the accompanying Consolidated Balance Sheet, net of accumulated depreciation, was $403 million and $357 million at December 31, 2014, and 2013, respectively. Computer software depreciation expense was $122 million, $90 million, and $59 million for the years ended December 31, 2014, 2013, and 2012, respectively, and is included as a component of Depreciation and amortization expense in the accompanying Consolidated Statement of Income.

Income taxes

Income taxes

The Company accounts for deferred income taxes utilizing an asset and liability method, whereby deferred tax assets and liabilities are recognized based on the tax effect of temporary differences between the financial statements and the tax basis of assets and liabilities, as measured by current enacted tax rates. The Company also evaluates the need for a valuation allowance to reduce deferred tax assets to estimated recoverable amounts.

The Company’s policy for recording interest and penalties associated with uncertain tax positions is to record such items as a component of income before income taxes. Penalties are recorded in Other (gains) losses, net, and interest paid or received is recorded in Interest expense or Interest income, respectively, in the Consolidated Statement of Income. Amounts recorded for penalties and interest related to uncertain tax positions were immaterial for all years presented.

Concentration risk

Concentration risk

Approximately 83 percent of the Company’s full-time equivalent Employees are unionized and are covered by collective bargaining agreements. The Company manages this risk by maintaining positive relationships with its Employees and its Employees’ Representatives. The majority of the Company's unionized Employees, including its Pilots, Mechanics, Ramp, Operations, Provisioning and Freight Agents, Flight Attendants, Material Specialists, Dispatchers, Flight Crew Training Instructors, Flight Simulator Technicians, and Facilities Maintenance Technicians are in discussions on labor agreements or have labor agreements which will become amendable within one year. These Employee groups represent approximately 70 percent of the Company’s full-time equivalent Employees as of December 31, 2014.

The Company attempts to minimize its concentration risk with regards to its cash, cash equivalents, and its investment portfolio. This is accomplished by diversifying and limiting amounts among different counterparties, the type of investment, and the amount invested in any individual security or money market fund.

To manage risk associated with financial derivative instruments held, the Company selects and will periodically review counterparties based on credit ratings, limits its exposure to a single counterparty, and monitors the market position of the program and its relative market position with each counterparty. The Company also has agreements with counterparties containing early termination rights and/or bilateral collateral provisions whereby security is required if market risk exposure exceeds a specified threshold amount or credit ratings fall below certain levels. Collateral deposits provided to or held from counterparties serve to decrease, but not totally eliminate, the credit risk associated with the Company’s hedging program. See Note 10 for further information.

As of December 31, 2014, the Company operates an all-Boeing fleet, all of which are variations of the Boeing 737. Following the 2011 acquisition of AirTran, the Company also operated a fleet of Boeing 717's, but these aircraft were removed from the Company's operations prior to the end of 2014. See Note 7 for further information. If the Company were unable to acquire additional aircraft or associated aircraft parts from Boeing, or Boeing were unable or unwilling to make timely deliveries of aircraft or to provide adequate support for its products, the Company’s operations would be materially adversely impacted. In addition, the Company would be materially adversely impacted in the event of a mechanical or regulatory issue associated with the Boeing 737 aircraft type, whether as a result of downtime for part or all of the Company’s fleet or because of a negative perception by the flying public. The Company is also dependent on sole suppliers for aircraft engines and certain other aircraft parts and would, therefore, also be materially adversely impacted in the event of the unavailability of, or a mechanical or regulatory issue associated with, engines and other parts.

The Company has historically entered into agreements with some of its co-brand, payment, and loyalty partners that contain exclusivity aspects which place certain confidential restrictions on the Company from entering into certain arrangements with other payment and loyalty partners. These arrangements generally extend for the terms of the partnerships, none of which currently extend beyond May 2017. The Company believes the financial benefits generated by the exclusivity aspects of these arrangements outweigh the risks involved with such agreements.

Derivatives

The Company is party to certain interest rate swap agreements that are accounted for as either fair value hedges or cash flow hedges, as defined in the applicable accounting guidance for derivative instruments and hedging. Several of the Company's interest rate swap agreements qualify for the “shortcut” method of accounting for hedges, which dictates that the hedges are assumed to be perfectly effective, and, thus, there is no ineffectiveness to be recorded in earnings. For the Company’s interest rate swap agreements that do not qualify for the "shortcut" method of accounting, ineffectiveness is required to be measured at each reporting period

Upon proper qualification, the Company accounts for its fuel derivative instruments as cash flow hedges. Generally, utilizing hedge accounting, all periodic changes in fair value of the derivatives designated as hedges that are considered to be effective are recorded in Accumulated Other Comprehensive Income (Loss) ("AOCI") until the underlying jet fuel is consumed. See Note 12. The Company’s results are subject to the possibility that periodic changes will not be effective, as defined, or that the derivatives will no longer qualify for hedge accounting. Ineffectiveness results when the change in the fair value of the derivative instrument exceeds the change in the value of the Company’s expected future cash outlay to purchase and consume jet fuel. To the extent that the periodic changes in the fair value of the derivatives are ineffective, the ineffective portion is recorded to Other (gains) losses, net in the Consolidated Statement of Income. Likewise, if a hedge ceases to qualify for hedge accounting, any change in the fair value of derivative instruments since the last reporting period is recorded to Other (gains) losses, net, in the Consolidated Statement of Income in the period of the change; however, any amounts previously recorded to AOCI would remain there until such time as the original forecasted transaction occurs, at which time these amounts would be reclassified to Fuel and oil expense. When the Company has sold derivative positions in order to effectively “close” or offset a derivative already held as part of its fuel derivative instrument portfolio, any subsequent changes in fair value of those positions are marked to market through earnings. Likewise, any changes in fair value of those positions that were offset by entering into the sold positions and were de-designated as hedges, are concurrently marked to market through earnings. However, any changes in value related to hedges that were deferred as part of AOCI while designated as a hedge would remain until the originally forecasted transaction occurs. In a situation where it becomes probable that a fuel hedged forecasted transaction will not occur, any gains and/or losses that have been recorded to AOCI would be required to be immediately reclassified into earnings. The Company did not have any such situations occur during 2012, 2013, or 2014.

In some situations, an entire commodity type used in hedging may cease to qualify for special hedge accounting treatment

Ineffectiveness is inherent in hedging jet fuel with derivative positions based in other crude oil related commodities. Due to the volatility in markets for crude oil and related products, the Company is unable to predict the amount of ineffectiveness each period, including the loss of hedge accounting, which could be determined on a derivative by derivative basis or in the aggregate for a specific commodity. This may result, and has resulted, in increased volatility in the Company’s financial results. Factors that have and may continue to lead to ineffectiveness and unrealized gains and losses on derivative contracts include: significant fluctuation in energy prices, the number of derivative positions the Company holds, significant weather events affecting refinery capacity and the production of refined products, and the volatility of the different types of products the Company uses in hedging. However, even though derivatives may not qualify for hedge accounting, the Company continues to hold the instruments as management believes derivative instruments continue to afford the Company the opportunity to stabilize jet fuel costs.

Accounting pronouncements pertaining to derivative instruments and hedging are complex with stringent requirements, including the documentation of a Company hedging strategy, statistical analysis to qualify a commodity for hedge accounting both on a historical and a prospective basis, and strict contemporaneous documentation that is required at the time each hedge is designated by the Company. The Company also examines the effectiveness of each individual hedge and its entire hedging program on a quarterly basis utilizing statistical analysis. This analysis involves utilizing regression and other statistical analyses that compare changes in the price of jet fuel to changes in the prices of the commodities used for hedging purposes

All of the Company's fuel derivative instruments and interest rate swaps are subject to agreements that follow the netting guidance in the applicable accounting for derivatives and hedging. The types of derivative instruments the Company has determined are subject to netting requirements in the accompanying Consolidated Balance Sheet are those in which the Company pays or receives cash for transactions with the same counterparty and in the same currency via one net payment or receipt. For cash collateral held by the Company or provided to counterparties, the Company nets such amounts against the fair value of the Company's derivative portfolio by each counterparty. The Company has elected to utilize netting for both its fuel derivative instruments and interest rate swap agreements and also classifies such amounts as either current or noncurrent, based on the net fair value position with each of the Company's counterparties in the Consolidated Balance Sheet.

The Company's application of its netting policy associated with cash collateral differs depending on whether its derivative instruments are in a net asset position or a net liability position. If its fuel derivative instruments are in a net asset position with a counterparty, cash collateral amounts held are first netted against current outstanding derivative amounts associated with that counterparty until that balance is zero, and then any remainder is applied against the fair value of noncurrent outstanding derivative instruments. If the Company's fuel derivative instruments are in a net liability position with the counterparty, cash collateral amounts provided are first netted against noncurrent outstanding derivative amounts associated with that counterparty until that balance is zero, and then any remainder is applied against the fair value of current outstanding derivative instruments

Compensation Related Costs

A portion of the Company’s granted options qualify as incentive stock options for income tax purposes. As such, a tax benefit is not recorded at the time the compensation cost related to the options is recorded for book purposes due to the fact that an incentive stock option does not ordinarily result in a tax benefit unless there is a disqualifying disposition. Grants of non-qualified stock options result in the creation of a deferred tax asset, which is a temporary difference, until the time that the option is exercised. Due to the treatment of incentive stock options for tax purposes, the Company’s effective tax rate from year to year is subject to variability.

Employee Retirement Plans

Unrecognized prior service cost is expensed using a straight-line amortization of the cost over the average future service of Employees expected to receive benefits under the plans. Actuarial gains are amortized utilizing the minimum amortization method. The following actuarial assumptions were used to account for the Company’s postretirement benefit plans at December 31, 2014, 2013, and 2012:

2014

2013

2012

Weighted-average discount rate

4.1

%

5.05

%

2.9

%

Assumed healthcare cost trend rate (1)

6.88

%

7.5

%

8

%

-1

The assumed healthcare cost trend rate is assumed to remain at 6.88% for 2015, then decline gradually to 5.00% by 2025 and remain level thereafter.

The assumed healthcare cost trend rates have a significant effect on the amounts reported for the consolidated postretirement plans. A one percent change in all healthcare cost trend rates used in measuring the APBO at December 31, 2014, would have the following effects:

(in millions)

1% increase

1% decrease

Increase (decrease) in total service and interest costs

$

3

$

(2

)

Increase (decrease) in the APBO

$

24

$

(20

)

The selection of a discount rate is made annually and is selected by the Company based upon comparison of the expected future cash flows associated with the Company’s future payments under its consolidated postretirement obligations to a yield curve created using high quality bonds that closely match those expected future cash flows. This rate decreased during 2014 due to market conditions. The assumed healthcare trend rate is also reviewed at least annually and is determined based upon both historical experience with the Company’s healthcare benefits paid and expectations of how those trends may or may not change in future years.

Summary_of_Significant_Account1

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
Schedule Of Finite Lived Intangible Assets	The following table is a summary of the Company’s intangible assets, which are included as a component of Other assets in the Company's Consolidated Balance Sheet, as of December 31, 2014 and 2013:
			Year ended December 31, 2014				Year ended December 31, 2013
	(in millions)	Weighted-average useful life (in years)	Gross carrying		Accumulated		Gross carrying amount		Accumulated Amortization
			amount		amortization
	Customer relationships/marketing agreements	9	$	38	$	26	$	39	$	23
	Trademarks/trade names	6	36		30		36		25
	Owned domestic slots	Indefinite	303		n/a		93		n/a
	Leased domestic slots (a)	39	19		5		19		4
	Non-compete agreements	2	5		5		5		5
	Gate leasehold rights	19	60		32		60		29
	Total	15	$	461	$	98	$	252	$	86
	(a) Useful life of leased slots is based on the stated lease term.

Net_Income_Per_Share_Tables

Net Income Per Share (Tables)	12 Months Ended
	Dec. 31, 2014
Earnings Per Share [Abstract]
Schedule Of Earnings Per Share Basic And Diluted	The following table sets forth the computation of basic and diluted net income per share (in millions except per share amounts):
		Year ended December 31,
		2014		2013		2012
	NUMERATOR:
	Net income	$	1,136	$	754	$	421
	Incremental income effect of	4		3		3
	interest on 5.25% convertible notes
	Net income after assumed conversion	$	1,140	$	757	$	424
	DENOMINATOR:
	Weighted-average shares outstanding, basic	687		710		750
	Dilutive effect of Employee stock options and	3		2		1
	restricted stock units
	Dilutive effect of 5.25% convertible notes	6		6		6
	Adjusted weighted-average shares outstanding, diluted	696		718		757
	NET INCOME PER SHARE:
	Basic	$	1.65	$	1.06	$	0.56
	Diluted	$	1.64	$	1.05	$	0.56
	Potentially dilutive amounts excluded from calculations:
	Stock options and restricted stock units	—		9		35

Commitments_and_Contingencies_

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Contractual Purchase Commitments	As of December 31, 2014, the Company had firm deliveries and options for Boeing 737-700, 737-800, 737 MAX 7, and 737 MAX 8 aircraft as follows:
		The Boeing Company					The Boeing Company
		737 NG					737 MAX
		-700		-800	Options	Additional -700 A/C	-7	-8		Options	Total
		Firm		Firm			Firm	Firm
		Orders		Orders			Orders	Orders
	2015	—		19	—	16	—	—		—	35
	2016	31		—	11	4	—	—		—	46
	2017	15		—	12	—	—	14		—	41
	2018	10		—	12	—	—	13		—	35
	2019	—		—	—	—	15	10		—	25
	2020	—		—	—	—	14	22		—	36
	2021	—		—	—	—	1	33		18	52
	2022	—		—	—	—	—	30		19	49
	2023	—		—	—	—	—	24		23	47
	2024	—		—	—	—	—	24		23	47
	2025	—		—	—	—	—	—		36	36
	2026	—		—	—	—	—	—		36	36
	2027	—		—	—	—	—	—		36	36
	Total	56	-1	19	35	20	30	170	-2	191	521
	(1) The Company has flexibility to substitute 737-800s in lieu of 737-700 firm orders.
	(2) The Company has flexibility to substitute MAX 7 in lieu of  MAX 8 firm orders beginning in 2019.

Recovered_Sheet2

Supplemental Financial Information (Tables)	12 Months Ended
	Dec. 31, 2014
Table Text Block [Abstract]
Other Assets
	(in millions)	31-Dec-14		31-Dec-13
	Derivative contracts	$	13	$	145
	Intangible assets	363		166
	Non-current investments	35		44
	Other	123		175
	Other assets	$	534	$	530
Accounts Payable
	(in millions)	31-Dec-14		31-Dec-13
	Accounts payable trade	$	123	$	189
	Salaries payable	160		156
	Taxes payable	163		146
	Aircraft maintenance payable	314		331
	Fuel payable	85		102
	Other payable	358		323
	Accounts payable	$	1,203	$	1,247
Accrued Liabilities
	(in millions)	31-Dec-14		31-Dec-13
	Profitsharing and savings plans	$	374	$	244
	Aircraft and other lease related obligations	159		173
	Vacation pay	292		278
	Health	84		73
	Derivative contracts	174		12
	Workers compensation	165		161
	Property and other taxes	81		65
	Other	236		223
	Accrued liabilities	$	1,565	$	1,229
Other Noncurrent Liabilities
	(in millions)	31-Dec-14		31-Dec-13
	Postretirement obligation	$	169	$	138
	Non-current lease-related obligations	193		290
	Other deferred compensation	174		163
	Deferred gains from sale and leaseback of aircraft	53		65
	Derivative contracts	622		45
	Other	44		70
	Other non-current liabilities	$	1,255	$	771

Longterm_Debt_Tables

Long-term Debt (Tables)	12 Months Ended
	Dec. 31, 2014
Debt Disclosure [Abstract]
Schedule of Long-term Debt Instruments
	(in millions)	31-Dec-14		31-Dec-13
	5.25% Notes due 2014	—		357
	5.75% Notes due 2016	313		320
	5.25% Convertible Senior Notes due 2016	113		115
	5.125% Notes due 2017	316		322
	Fixed-rate 717 Aircraft Notes payable through 2017—10.37%	—		41
	French Credit Agreements due 2018—1.06%	36		46
	Fixed-rate 737 Aircraft Notes payable through 2018—7.02%	24		30
	2.75% Notes due 2019	300		—
	Term Loan Agreement due 2019—6.315%	178		210
	Term Loan Agreement due 2019—6.84%	73		85
	Term Loan Agreement due 2020—5.223%	372		413
	Floating-rate 737 Aircraft Notes payable through 2020	300		340
	Pass Through Certificates due 2022—6.24%	355		371
	7.375% Debentures due 2027	134		136
	Capital leases (Note 7)	199		56
		$	2,713	$	2,842
	Less current maturities	258		629
	Less debt discount and issuance costs	21		22
		$	2,434	$	2,191

Leases_Tables

Leases (Tables)	12 Months Ended
	Dec. 31, 2014
Leases [Abstract]
Capital Leases Aircraft Included In Property And Equipment	Amounts applicable to these aircraft that are included in property and equipment were:
	(in millions)	2014			2013
	Flight equipment	$	214		$	69
	Less: accumulated amortization	22			12
		$	192		$	57
Future Minimum Lease Payments Under Capital Leases And Noncancelable Operating Leases	Future minimum lease payments under capital leases and noncancelable operating leases and rentals to be received under subleases with initial or remaining terms in excess of one year at December 31, 2014, were:
	(in millions)	Capital			Operating		Subleases			LFMP facility lease*		Operating
		leases			leases							leases, net
	2015	$	33		$	753	$	(93	)	$	24	$	684
	2016	42			715		(103		)	24		636
	2017	45			671		(103		)	24		592
	2018	44			573		(102		)	25		496
	2019	43			502		(97		)	25		430
	Thereafter	202			1,802		(144		)	659		2,317
	Total minimum lease payments	$	409		$	5,016	$	(642	)	$	781	$	5,155
	Less amount representing interest	75
	Present value of minimum lease payments	334
	Less current portion	23
	Long-term portion	$	311
	* See Note 4 for further details
Sublease Rollforward	A rollforward of the Company's B717 lease/sublease liability for 2014 and 2013 is shown below:
	(in millions)	B717 lease/sublease liability
	Balance at December 31, 2012	$	128
	Lease/sublease accretion	6
	Lease/sublease payments, net (a)	(12		)
	Balance at December 31, 2013	$	122
	Lease/sublease accretion	5
	Lease/sublease expense adjustment	22
	Lease/sublease payments, net (a)	(86		)
	Balance at December 31, 2014	$	63
	(a) Includes lease conversion cost payments

Stock_Plans_Tables

Stock Plans (Tables)	12 Months Ended
	Dec. 31, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Schedule of Share-based Compensation, Restricted Stock Units Award Activity	Aggregated information regarding the Company’s RSUs and PBRSUs is summarized below:
		All Restricted Stock Units
		Units (000)			Wtd. Average
					Fair Value
					(per share)
	Outstanding December 31, 2011, Unvested	1,640			$	12.27
	Granted	1,939			8.21
	Vested	(644	)		12.27
	Surrendered	(59	)		10.54
	Outstanding December 31, 2012	2,876			9.57
	Granted	1,139			14.34
	Vested	(1,263	)		10.24
	Surrendered	(168	)		9.11
	Outstanding December 31, 2013	2,584			11.38
	Granted	834		(a)	24.93
	Vested	(1,239	)		11.05
	Surrendered	(102	)		13.18
	Outstanding December 31, 2014, Unvested	2,077			$	16.92
	(a) Includes 198 thousand shares of PBRSUs
Schedule of Share-based Compensation, Stock Options, Activity	Aggregated information regarding Company issued stock options is summarized below:
		Stock Option Plans
		Options			Wtd.		Wtd.	Aggregate
		0			average		average	intrinsic
					exercise		remaining	value
					price		contractual	(millions)
							term
							(years)
	Outstanding December 31, 2011	47,324			$	14.51
	Granted	6			9
	Exercised	(573	)		8
	Surrendered	(27,847	)		14.85
	Outstanding December 31, 2012	18,910			$	14.19
	Granted	—			—
	Exercised	(6,633	)		13.31
	Surrendered	(3,116	)		14.94
	Outstanding December 31, 2013	9,161			$	14.58
	Granted	—			—
	Exercised	(6,636	)		14.36
	Surrendered	(48	)		15.74
	Outstanding December 31, 2014	2,477			$	15.17	1.62	$	67
	Vested or expected to vest at December 31, 2014	2,473			$	15.16	1.63	$	67
	Exercisable at December 31, 2014	2,308			$	15.05	1.67	$	63

Recovered_Sheet3

Financial Derivative Instruments (Tables)	12 Months Ended
	Dec. 31, 2014
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Volume of Fuel Hedging	The following table provides information about the Company’s volume of fuel hedging for the years 2015 through 2018 on an “economic” basis considering current market prices:
			Fuel hedged as of
			31-Dec-14			Derivative underlying commodity type as of
	Period (by year)		(gallons in millions)			31-Dec-14
	2015		—		(b)
	2016		885		(a)	Brent crude oil, Heating oil, and Gulf Coast jet fuel
	2017		757		(a)	WTI crude and Brent crude oil
	2018		—		(b)
	(a) Due to the types of derivatives utilized by the Company and different price levels of those contracts, these volumes represent the maximum economic hedge in place and may vary significantly as market prices fluctuate.
	(b) In response to the precipitous decline in oil and jet fuel prices during the second half of 2014, the Company took action to offset its 2015 and 2018 fuel derivative portfolios and is now effectively unhedged at current price levels. While the Company still holds derivative contracts as of December 31, 2014, that will settle during 2015 and 2018, the majority of the losses associated with those contracts are substantially locked in. However, if market prices were to increase or decrease significantly related to the 2015 positions prior to these contracts settling, the losses incurred at settlement could be slightly lower or higher than currently expected amounts during that period.
Schedule of Derivative Instruments in Statement of Financial Position, Fair Value	The following table presents the location of all assets and liabilities associated with the Company’s hedging instruments within the Consolidated Balance Sheet:
					Asset derivatives								Liability derivatives
			Balance Sheet		Fair value at				Fair value at				Fair value at				Fair value at
	(in millions)		location		12/31/14				12/31/13				12/31/14				12/31/13
	Derivatives designated as hedges*
	Fuel derivative contracts (gross)		Prepaid expenses and other current assets		$	—			$	74			$	—			$	—
	Fuel derivative contracts (gross)		Other assets		—				209				—				1
	Fuel derivative contracts (gross)		Other noncurrent liabilities		—				—				643				—
	Interest rate derivative contracts		Other assets		13				20				—				—
	Interest rate derivative contracts		Other noncurrent liabilities		—				—				61				77
	Total derivatives designated as hedges				$	13			$	303			$	704			$	78
	Derivatives not designated as hedges*
	Fuel derivative contracts (gross)		Prepaid expenses and other current assets		$	—			$	175			$	—			$	182
	Fuel derivative contracts (gross)		Other assets		—				16				—				99
	Fuel derivative contracts (gross)		Accrued liabilities		1,190				9				1,432				21
	Fuel derivative contracts (gross)		Other noncurrent liabilities		157				—				273				—
	Total derivatives not designated as hedges				$	1,347			$	200			$	1,705			$	302
	Total derivatives				$	1,360			$	503			$	2,409			$	380
	* Represents the position of each trade before consideration of offsetting positions with each counterparty and does not include the impact of cash collateral deposits provided to or received from counterparties. See discussion of credit risk and collateral following in this Note.
Cash Collateral Deposits Due To Or From Third Parties and Net Unrealized Losses	In addition, the Company also had the following amounts associated with fuel derivative instruments and hedging activities in its Consolidated Balance Sheet:
			Balance Sheet		December 31,				December 31,
	(in millions)		location		2014				2013
	Cash collateral deposits provided to counterparties for fuel		Offset against Accrued liabilities		$	68			$	—
	contracts - current
	Cash collateral deposits provided to counterparties for fuel		Offset against Other noncurrent liabilities		198				—
	contracts- noncurrent
	Cash collateral deposits provided to counterparties for interest		Offset against Other noncurrent liabilities		—				32
	rate contracts - noncurrent
	Due to third parties for fuel contracts		Accrued liabilities		16				—
	Receivable from third parties for fuel contracts - current		Accounts and other receivables		—				57
Offsetting Assets	The Company has the following recognized financial assets and financial liabilities resulting from those transactions that meet the scope of the disclosure requirements as necessitated by applicable accounting guidance for balance sheet offsetting:
	Offsetting of derivative assets
	(in millions)
					(i)				(ii)				(iii) =i) + (ii)				(i)				(ii)				(iii) =i) + (ii)
					December 31, 2014												31-Dec-13
	Description		Balance Sheet location		Gross amounts of recognized assets				Gross amounts offset in the Balance Sheet				Net amounts of assets presented in the Balance Sheet				Gross amounts of recognized assets				Gross amounts offset in the Balance Sheet				Net amounts of assets presented in the Balance Sheet
	Fuel derivative contracts		Prepaid expenses and other current assets		$	—			$	—			$	—			$	249			$	(182	)		$	67
	Fuel derivative contracts		Other assets		$	—			$	—			$	—		(a)	$	225			$	(100	)		$	125		(a)
	Fuel derivative contracts		Accrued liabilities		$	1,258			$	(1,258	)		$	—		(a)	$	9			$	(9	)		$	—		(a)
	Fuel derivative contracts		Other noncurrent liabilities		$	355			$	(355	)		$	—		(a)	$	—			$	—			$	—		(a)
	Interest rate derivative contracts		Other assets		$	13			$	—			$	13		(a)	$	20			$	—			$	20		(a)
	(a) The net amounts of derivative assets and liabilities are reconciled to the individual line item amounts presented in the Consolidated Balance Sheet in Note 5.
Offsetting Liabilities
	Offsetting of derivative liabilities
	(in millions)
					(i)				(ii)				(iii) =i) + (ii)				(i)				(ii)				(iii) =i) + (ii)
					December 31, 2014												31-Dec-13
	Description		Balance Sheet location		Gross amounts of recognized liabilities				Gross amounts offset in the Balance Sheet				Net amounts of liabilities presented in the Balance Sheet				Gross amounts of recognized liabilities				Gross amounts offset in the Balance Sheet				Net amounts of liabilities presented in the Balance Sheet
	Fuel derivative contracts		Prepaid expenses and other current assets		$	—			$	—			$	—			$	182			$	(182	)		$	—
	Fuel derivative contracts		Other assets		$	—			$	—			$	—		(a)	$	100			$	(100	)		$	—		(a)
	Fuel derivative contracts		Accrued liabilities		$	1,432			$	(1,258	)		$	174		(a)	$	21			$	(9	)		$	12		(a)
	Fuel derivative contracts		Other noncurrent liabilities		$	916			$	(355	)		$	561		(a)	$	—			$	—			$	—		(a)
	Interest rate derivative contracts		Other noncurrent liabilities		$	61			$	—			$	61		(a)	$	77			$	(32	)		$	45		(a)
	(a) The net amounts of derivative assets and liabilities are reconciled to the individual line item amounts presented in the Consolidated Balance Sheet in Note 5.
Derivatives in Cash Flow Hedging Relationships	The following tables present the impact of derivative instruments and their location within the Consolidated Statement of Income for the year ended December 31, 2014 and 2013:
	Derivatives in cash flow hedging relationships
		(Gain) loss recognized in AOCI on derivatives (effective portion)								(Gain) loss reclassified from AOCI into income (effective portion)(a)								(Gain) loss recognized in income on derivatives (ineffective portion)(b)
		Year ended								Year ended								Year ended
		December 31,								December 31,								December 31,
	(in millions)	2014				2013				2014				2013				2014				2013
	Fuel derivative contracts	$	749		*	$	52		*	$	22		*	$	103		*	$	7			$	10
	Interest rate derivatives	6			*	(14		)	*	14			*	18			*	(4		)		1
	Total	$	755			$	38			$	36			$	121			$	3			$	11
	*Net of tax
	(a) Amounts related to fuel derivative contracts and interest rate derivatives are included in Fuel and oil and Interest expense, respectively.
	(b) Amounts are included in Other (gains) losses, net.
Derivatives Not in Cash Flow Hedging Relationships
	Derivatives not in cash flow hedging relationships
		(Gain) loss
		recognized in income on
		derivatives
		Year ended								Location of (gain) loss
		December 31,								recognized in income
	(in millions)	2014				2013				on derivatives
	Fuel derivative contracts	$	244			$	(100	)		Other (gains) losses, net
Fair Values of Fuel Derivatives, Amounts Posted as Collateral, and Collateral Posting Threshold Amounts	The following table provides the fair values of fuel derivatives, amounts posted as collateral, and applicable collateral posting threshold amounts as of December 31, 2014, at which such postings are triggered:
		Counterparty (CP)
	(in millions)	A				B				C				D				E				F				Other(a)			Total
	Fair value of fuel derivatives	$	(333	)		$	(136	)		$	(122	)		$	(219	)		$	(66	)		$	(86	)		$	(39	)	$	(1,001	)
	Cash collateral held (by) CP	(50		)		(98		)		(57		)		—				(23		)		(38		)		—			(266		)
	Aircraft collateral pledged to CP	(134		)		—				—				—				—				—				—			(134		)
	Letters of credit (LC)	(100		)		—				—				(150		)		—				—				—			(250		)
	Option to substitute LC for aircraft	<(400)(g)				(100) to (500)(d)				N/A				(150) to (550)(d)				N/A				N/A
	Option to substitute LC for cash	(50) to (150)(d)				>(500)				(100) to (150)(e)				(75) to (150) or >(550)(d)				N/A				(f)
	If credit rating is investment
	grade, fair value of fuel
	derivative level at which:
	Cash is provided to CP	(50) to (200) or >(600)				(50) to (100) or >(500)				>(75)				(75) to (150) or >(550)				>(50)				>(50)
	Cash is received from CP	>50				>150				>175(c)				>200				>30				>(50)
	Aircraft or cash can be pledged to	(200) to (600)(d)				(100) to (500)(d)				N/A				(150) to (550)(d)				N/A				N/A
	CP as collateral
	If credit rating is non-investment
	grade, fair value of fuel derivative
	level at which:
	Cash is provided to CP	(0) to (200) or >(600)				(0) to (100) or >(500)				(b)				(0) to (150) or >(550)				(b)				(b)
	Cash is received from CP	(b)				(b)				(b)				(b)				(b)				(b)
	Aircraft or cash can be pledged to	(200) to (600)				(100) to (500)				N/A				(150) to (550)				N/A				N/A
	CP as collateral
	(a) Individual counterparties with fair value of fuel derivatives <$25 million.
	(b) Cash collateral is provided at 100 percent of fair value of fuel derivative contracts.
	(c) Thresholds may vary based on changes in credit ratings within investment grade.
	(d) The Company has the option of providing cash, letters of credit, or pledging aircraft as collateral.
	(e) The Company has the option of providing cash or letters of credit as collateral.
	(f) The Company has the option to substitute letters of credit for 100 percent of cash collateral requirement.
	(g) The Company has the option of providing letters of credit in addition to aircraft collateral if the appraised value of the aircraft does not meet the collateral requirements.

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2014
Fair Value Disclosures [Abstract]
Assets and Liabilities Measured at Fair Value on a Recurring Basis	The following tables present the Company’s assets and liabilities that are measured at fair value on a recurring basis at December 31, 2014, and December 31, 2013:
							Fair value measurements at reporting date using:
							Quoted prices in				Significant				Significant
							active markets				other observable				unobservable
							for identical assets				inputs				inputs
	Description		December 31, 2014				(Level 1)				(Level 2)				(Level 3)
	Assets		(in millions)
	Cash equivalents
	Cash equivalents (a)		$	1,110			$	1,110			$	—			$	—
	Commercial paper		70				—				70				—
	Certificates of deposit		4				—				4				—
	Eurodollar Time Deposits		98				—				98				—
	Short-term investments:
	Treasury bills		1,450				1,450				—				—
	Certificates of deposit		256				—				256				—
	Noncurrent investments (b)
	Auction rate securities		27				—				—				27
	Interest rate derivatives (see Note 10)		13				—				13				—
	Fuel derivatives:
	Swap contracts (c)		455				—				455				—
	Option contracts (c)		892				—				—				892
	Other available-for-sale securities		68				63				—				5
	Total assets		$	4,443			$	2,623			$	896			$	924
	Liabilities
	Fuel derivatives:
	Swap contracts (c)		$	(365	)		$	—			$	(365	)		$	—
	Option contracts (c)		(1,983		)		—				—				(1,983		)
	Interest rate derivatives (see Note 10)		(61		)		—				(61		)		—
	Total liabilities		$	(2,409	)		$	—			$	(426	)		$	(1,983	)
	(a) Cash equivalents are primarily composed of money market investments.
	(b) Noncurrent investments are included in Other assets in the Consolidated Balance Sheet.
	(c) In the Consolidated Balance Sheet amounts are presented as a net liability. See Note 10.
							Fair value measurements at reporting date using:
							Quoted prices in				Significant				Significant
							active markets				other observable				unobservable
							for identical assets				inputs				inputs
	Description		December 31, 2013				(Level 1)				(Level 2)				(Level 3)
	Assets		(in millions)
	Cash equivalents
	Cash equivalents (a)		$	992			$	992			$	—			$	—
	Commercial paper		280				—				280				—
	Certificates of deposit		23				—				23				—
	Eurodollar Time Deposits		60				—				60				—
	Short-term investments:
	Treasury bills		1,570				1,570				—				—
	Certificates of deposit		227				—				227				—
	Noncurrent investments (b)
	Auction rate securities		39				—				—				39
	Interest rate derivatives (see Note 10)		20				—				20				—
	Fuel derivatives:
	Swap contracts (c)		16				—				16				—
	Option contracts (c)		458				—				—				458
	Option contracts (d)		9				—				—				9
	Other available-for-sale securities		63				58				—				5
	Total assets		$	3,757			$	2,620			$	626			$	511
	Liabilities
	Fuel derivatives:
	Swap contracts (c)		$	(8	)		$	—			$	(8	)		$	—
	Option contracts (c)		(274		)		—				—				(274		)
	Swap contracts (d)		(21		)		—				—				(21		)
	Interest rate derivatives (see Note 10)		(77		)		—				(77		)		—
	Total liabilities		$	(380	)		$	—			$	(85	)		$	(295	)
	(a) Cash equivalents are primarily composed of money market investments.
	(b) Noncurrent investments are included in Other assets in the Consolidated Balance Sheet.
(c) In the Consolidated Balance Sheet amounts are presented as a net asset. See Note 10.
(d) In the Consolidated Balance Sheet amounts are presented as a net liability. See Note 10.
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation	The following tables present the Company’s activity for items measured at fair value on a recurring basis using significant unobservable inputs (Level 3) for 2014 and 2013:
		Fair value measurements using significant
		unobservable inputs (Level 3)
		Fuel				Auction rate				Other
	(in millions)	derivatives				securities				securities				Total
	Balance at December 31, 2013	$	172			$	39			$	5			$	216
	Total gains or (losses) (realized or unrealized)
	Included in earnings	(439		)		—				—				(439		)
	Included in other comprehensive income	(1,091		)		3				—				(1,088		)
	Purchases	403			(a)	—				—				403
	Sales	(155		)	(a)	(15		)		—				(170		)
	Settlements	19				—				—				19
	Balance at December 31, 2014	$	(1,091	)		$	27		(b)	$	5			$	(1,059	)
	The amount of total losses for the period	$	(450	)		$	—			$	—			$	(450	)
	included in earnings attributable to the
	change in unrealized gains or losses relating
	to assets still held at December 31, 2014
	(a) The purchase and sale of fuel derivatives are recorded gross based on the structure of the derivative instrument and
	whether a contract with multiple derivatives is purchased as a single instrument or separate instruments.
	(b) Included in Other assets in the Consolidated Balance Sheet.
		Fair value measurements using significant
		unobservable inputs (Level 3)
		Fuel				Auction rate				Other
	(in millions)	derivatives				securities				securities				Total
	Balance at December 31, 2012	$	219			$	36			$	5			$	260
	Total gains or (losses) (realized or unrealized)
	Included in earnings	71				—				—				71
	Included in other comprehensive income	(107		)		3				—				(104		)
	Purchases	357			(a)	—				—				357
	Sales	(417		)	(a)	—				—				(417		)
	Settlements	49				—				—				49
	Balance at December 31, 2013	$	172			$	39		(b)	$	5			$	216
	The amount of total gains for the period	$	86			$	—			$	—			$	86
	included in earnings attributable to the
	change in unrealized gains or losses relating
	to assets still held at December 31, 2013
	(a) The purchase and sale of fuel derivatives are recorded gross based on the structure of the derivative instrument and
	whether a contract with multiple derivatives is purchased as a single instrument or separate instruments.
	(b) Included in Other assets in the Consolidated Balance Sheet.
Fair Value Valuation Techniques	The following table presents a range of the unobservable inputs utilized in the fair value measurements of the Company’s assets and liabilities classified as Level 3 at December 31, 2014:
	Quantitative information about Level 3 fair value measurements
		Valuation technique	Unobservable input	Period (by year)	Range
	Fuel derivatives	Option model	Implied volatility	2015	23-47%
				2016	24-36%
				2017	19-30%
				2018	25-27%
	Auction rate securities	Discounted cash flow	Time to principal recovery		8 years
			Illiquidity premium		3%
			Counterparty credit spread		1-2%
Fair value, by Balance Sheet Grouping
	(in millions)	Carrying value			Estimated fair value			Fair value level hierarchy
	5.75% Notes due 2016	313			335			Level 2
	5.25% Convertible Senior Notes due 2016	113			318			Level 2
	5.125% Notes due 2017	316			338			Level 2
	French Credit Agreements due 2018 - 1.06%	36			36			Level 3
	Fixed-rate 737 Aircraft Notes payable through 2018 - 7.02%	24			25			Level 3
	2.75% Notes due 2019	300			304			Level 2
	Term Loan Agreement due 2019 - 6.315%	178			178			Level 3
	Term Loan Agreement due 2019 - 6.84%	73			79			Level 3
	Term Loan Agreement due 2020 - 5.223%	372			367			Level 3
	Floating-rate 737 Aircraft Notes payable through 2020	300			293			Level 3
	Pass Through Certificates due 2022 - 6.24%	355			410			Level 2
	7.375% Debentures due 2027	134			160			Level 2

Recovered_Sheet4

Accumulated Other Comprehensive Income (Loss) (Tables)	12 Months Ended
	Dec. 31, 2014
Equity [Abstract]
Rollforward of the Amounts Included in AOCI, Net of Taxes	A rollforward of the amounts included in AOCI, net of taxes, is shown below for 2014 and 2013:
	(in millions)	Fuel derivatives			Interest rate derivatives			Defined benefit plan items			Other			Deferred tax impact		Accumulated other
																comprehensive income (loss)
	Balance at December 31, 2012	$	(103	)	$	(108	)	$	26		$	(8	)	$	74	$	(119	)
	changes in fair value	(82		)	22			39			16			—		(5		)
	Reclassification to earnings	165			28			—			—			-72		121
	Balance at December 31, 2013	$	(20	)	$	(58	)	$	65		$	8		$	2	$	(3	)
	changes in fair value	(1,191		)	(10		)	(24		)	—			454		(771		)
	Reclassification to earnings	34			23			—			—			-21		36
	Balance at December 31, 2014	$	(1,177	)	$	(45	)	$	41		$	8		$	435	$	(738	)
Reclassification out of Accumulated Other Comprehensive Income	The following table illustrates the significant amounts reclassified out of each component of AOCI for the year ended December 31, 2014:
	Year ended December 31, 2014
	(in millions)		Amounts reclassified from AOCI			Affected line item in the Consolidated Statement of Comprehensive Income
	AOCI components
	Unrealized gain on fuel derivative instruments		$	34		Fuel and oil expense
			12			Less: Tax expense
			$	22		Net of tax
	Unrealized gain on interest rate derivative instruments		$	23		Interest expense
			9			Less: Tax expense
			$	14		Net of tax
	Total reclassifications for the period		$	36		Net of tax

Employee_Retirement_Plans_Tabl

Employee Retirement Plans (Tables)	12 Months Ended
	Dec. 31, 2014
Compensation and Retirement Disclosure [Abstract]
Schedule of Changes in Accumulated Postemployment Benefit Obligations	The following table shows the change in the accumulated postretirement benefit obligation (APBO) for the years ended December 31, 2014 and 2013:
	(in millions)		2014				2013
	APBO at beginning of period		$	138			$	148
	Service cost		10				30
	Interest cost		7				4
	Benefits paid		(4		)		(3		)
	Actuarial (gain)/loss		21				(41		)
	Settlements		$	(3	)		$	—
	APBO at end of period		$	169			$	138
Schedule of Amounts Recognized in Balance Sheet	The following table reconciles the funded status of the plans to the accrued postretirement benefit cost recognized in Other non-current liabilities on the Company’s Consolidated Balance Sheet at December 31, 2014 and 2013.
	(in millions)		2014				2013
	Funded status		$	(169	)		$	(138	)
	Unrecognized net actuarial gain		(53		)		(80		)
	Unrecognized prior service cost		12				15
	Accumulated other comprehensive income		41				65
	Cost recognized on Consolidated Balance Sheet		$	(169	)		$	(138	)
Schedule of Net Benefit Costs	The consolidated periodic postretirement benefit cost for the years ended December 31, 2014, 2013, and 2012, included the following:
	(in millions)		2014				2013				2012
	Service cost		$	10			$	30			$	20
	Interest cost		7				4				4
	Amortization of prior service cost		3				3				—
	Recognized actuarial gain		(4		)		(4		)		(5		)
	Settlements		$	(1	)		$	—			$	—
	Net periodic postretirement benefit cost		$	15			$	33			$	19
Schedule of Assumptions Used	The following actuarial assumptions were used to account for the Company’s postretirement benefit plans at December 31, 2014, 2013, and 2012:
			2014			2013			2012
	Weighted-average discount rate		4.1	%		5.05	%		2.9	%
	Assumed healthcare cost trend rate (1)		6.88	%		7.5	%		8	%
	-1	The assumed healthcare cost trend rate is assumed to remain at 6.88% for 2015, then decline gradually to 5.00% by 2025 and remain level thereafter.
Schedule of Effect of One-Percentage-Point Change in Assumed Health Care Cost Trend Rates
	(in millions)		1% increase				1% decrease
	Increase (decrease) in total service and interest costs		$	3			$	(2	)
	Increase (decrease) in the APBO		$	24			$	(20	)

Income_Taxes_Tables

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Components of Deferred Tax Assets and Liabilities	The components of deferred tax assets and liabilities at December 31, 2014 and 2013, are as follows:
	(in millions)	2014			2013
	DEFERRED TAX LIABILITIES:
	Accelerated depreciation	$	4,277		$	4,069
	Fuel derivative instruments	—			36
	Other	51			84
	Total deferred tax liabilities	4,328			4,189
	DEFERRED TAX ASSETS:
	Fuel derivative instruments	521			8
	Deferred gains from sale and leaseback of aircraft	20			24
	Capital and operating leases	125			163
	Construction obligation	209			168
	Accrued engine maintenance	83			90
	Accrued employee benefits	334			307
	State taxes	65			74
	Business partner income	90			457
	Net operating losses and credit carryforwards	3			14
	Other	96			118
	Total deferred tax assets	1,546			1,423
	Net deferred tax liability	$	2,782		$	2,766
Components of the Income Tax Provision	The provision for income taxes is composed of the following:
	(in millions)	2014			2013			2012
	CURRENT:
	Federal	$	203		$	355		$	(45	)
	State	29			44			12
	Total current	232			399			(33		)
	DEFERRED:
	Federal	421			62			287
	State	27			(6		)	10
	Total deferred	448			56			297
		$	680		$	455		$	264
Income Tax Provision Reconciliation To Federal Income Tax Statutory Rate	The effective tax rate on income before income taxes differed from the federal income tax statutory rate for the following reasons:
	(in millions)	2014			2013			2012
	Tax at statutory U.S. tax rates	$	636		$	423		$	240
	Nondeductible items	9			10			10
	State income taxes, net of federal benefit	37			25			14
	Other, net	(2		)	(3		)	—
	Total income tax provision	$	680		$	455		$	264

Quarterly_Financial_Data_Table

Quarterly Financial Data (Tables)	12 Months Ended
	Dec. 31, 2014
Quarterly Financial Data [Abstract]
Schedule of Quarterly Financial Information
		Three months ended
	(in millions except per share amounts)	March 31		June 30		Sept. 30		Dec. 31
	2014
	Operating revenues	$	4,166	$	5,011	$	4,800	$	4,628	(a)
	Operating income	215		775		614		621
	Income before income taxes	244		746		525		302
	Net income	152		465		329		190
	Net income per share, basic	0.22		0.67		0.48		0.28		(a)
	Net income per share, diluted	0.22		0.67		0.48		0.28		(a)
		31-Mar		30-Jun		Sept. 30		Dec. 31
	2013
	Operating revenues	$	4,084	$	4,643	$	4,545	$	4,428
	Operating income	70		433		390		386
	Income (loss) before income taxes	94		363		419		334
	Net income (loss)	59		224		259		212
	Net income (loss) per share, basic	0.08		0.31		0.37		0.3
	Net income (loss) per share, diluted	0.08		0.31		0.37		0.3
	(a) Includes a change in estimate, recorded on a prospective basis, effective October 1, 2014, which increased Passenger revenues by approximately $55 million and increased both Basic and Diluted net income per share by $.04. See Note 1 for further detail.

Summary_of_Significant_Account2

Summary of Significant Accounting Policies (Details) (USD $)	12 Months Ended					3 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012	Dec. 31, 2012	Dec. 31, 2014
Accounting Policies [Abstract]
Prior Period Reclassification Adjustment			($14,000,000)
Inventory reserve for obsolescence	46,000,000		36,000,000				46,000,000
The percentage of the amount received per flight segment sold that relate to free travel-SWA (in hundredths)	100.00%
Frequent flyer points and flight credits liability	1,300,000,000		1,100,000,000				1,300,000,000
Capitalized computer software, net	403,000,000		357,000,000				403,000,000
Computer software depreciation expense	122,000,000		90,000,000		59,000,000
Advertising costs	207,000,000		208,000,000		223,000,000
Concentration Risk [Line Items]
The percentage of employees subject to amendable agreements in the current year (in hundredths)	70.00%						70.00%
Acquired Finite-Lived Intangible Assets [Line Items]
Gross carrying amount (in millions) (a)	461,000,000		252,000,000				461,000,000
Weighted-average useful life (in years)	15 years
Accumulated amortization (in millions) (a)	98,000,000		86,000,000				98,000,000
Amortization of intangible assets	13,000,000		19,000,000		25,000,000
Finite-Lived Intangible Assets, Future Amortization Expense [Abstract]
2015	11,000,000						11,000,000
2016	8,000,000						8,000,000
2017	5,000,000						5,000,000
2018	5,000,000						5,000,000
2019	4,000,000						4,000,000
Thereafter	27,000,000						27,000,000
Customer relationships/marketing agreements
Acquired Finite-Lived Intangible Assets [Line Items]
Gross carrying amount of finite-lived intangible assets	38,000,000		39,000,000				38,000,000
Weighted-average useful life (in years)	9 years
Accumulated amortization (in millions) (a)	26,000,000		23,000,000				26,000,000
Trademarks/trade names
Acquired Finite-Lived Intangible Assets [Line Items]
Gross carrying amount of finite-lived intangible assets	36,000,000		36,000,000				36,000,000
Weighted-average useful life (in years)	6 years
Accumulated amortization (in millions) (a)	30,000,000		25,000,000				30,000,000
Owned domestic slots
Acquired Finite-Lived Intangible Assets [Line Items]
Gross carrying amount of indefinite-lived intangible assets	303,000,000		93,000,000				303,000,000
Contract-Based Intangible Assets [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Gross carrying amount of finite-lived intangible assets	19,000,000	[1]	19,000,000	[1]			19,000,000	[1]
Weighted-average useful life (in years)	39 years	[1]
Accumulated amortization (in millions) (a)	5,000,000	[1]	4,000,000	[1]			5,000,000	[1]
Non-compete agreements
Acquired Finite-Lived Intangible Assets [Line Items]
Gross carrying amount of finite-lived intangible assets	5,000,000		5,000,000				5,000,000
Weighted-average useful life (in years)	2 years
Accumulated amortization (in millions) (a)	5,000,000		5,000,000				5,000,000
Gate leasehold rights
Acquired Finite-Lived Intangible Assets [Line Items]
Gross carrying amount of finite-lived intangible assets	60,000,000		60,000,000				60,000,000
Weighted-average useful life (in years)	19 years
Accumulated amortization (in millions) (a)	32,000,000		29,000,000				32,000,000
Flight equipment
Property, Plant and Equipment [Line Items]
Minimum percentage of cost estimated residual value (in hundredths)	2.00%
Maximum percentage of cost estimated as residual value (in hundredths)	20.00%
Flight equipment | Minimum
Property, Plant and Equipment [Line Items]
Property, Plant, and Equipment Useful Life	23 years
Flight equipment | Maximum
Property, Plant and Equipment [Line Items]
Property, Plant, and Equipment Useful Life	25 years
Property, Plant and Equipment [Member] | Minimum
Property, Plant and Equipment [Line Items]
Property, Plant, and Equipment Useful Life	5 years
Property, Plant and Equipment [Member] | Maximum
Property, Plant and Equipment [Line Items]
Property, Plant, and Equipment Useful Life	30 years
Ground property and equipment
Property, Plant and Equipment [Line Items]
Minimum percentage of cost estimated residual value (in hundredths)	0.00%
Maximum percentage of cost estimated as residual value (in hundredths)	10.00%
Software | Minimum
Property, Plant and Equipment [Line Items]
Property, Plant, and Equipment Useful Life	5 years 0 months 0 days
Software | Maximum
Property, Plant and Equipment [Line Items]
Property, Plant, and Equipment Useful Life	15 years 0 months 0 days
Change In Estimated Useful Life
Change in Accounting Estimate [Line Items]
Change In Accounting Estimate Financial Effect On Depreciation Expense					12,000,000
Change in accounting estimate, financial effect on net income					6,000,000
Change in accounting estimate, financial effect on net income per share (in dollars per share)					($0.01)
Change In Estimated Residual Values
Change in Accounting Estimate [Line Items]
Residual Values Percent Of Original Cost Subsequent To Change						2.00%
Change In Accounting Estimate Financial Effect On Depreciation Expense					34,000,000
Change in accounting estimate, financial effect on net income					18,000,000
Change in accounting estimate, financial effect on net income per share (in dollars per share)					$0.02
Residual Values Percent Of Original Cost Prior To Change						10.00%
Change in Spoilage Estimate [Domain]
Change in Accounting Estimate [Line Items]
Change in Accounting Estimate Financial Effect on Passenger Revenue							55,000,000
Change in accounting estimate, financial effect on net income, spoilage adjustment	29,000,000
Change in accounting estimate,financial effect on earnings per share	$0.04
Fuel derivatives
Accounting Policies [Abstract]
Total collateral already posted aggregate fair value	266,000,000		0				266,000,000
Other Noncurrent Liabilities | Fuel derivatives
Property, Plant and Equipment [Line Items]
Collateral Already Posted, Aggregate Fair Value	198,000,000		0				198,000,000
Other Noncurrent Liabilities | Interest rate derivatives
Property, Plant and Equipment [Line Items]
Collateral Already Posted, Aggregate Fair Value	$0		$32,000,000				$0
Unionized Employees concentration risk
Concentration Risk [Line Items]
The percentage of Company's employees that are unionized and covered by collective bargaining agreements (in hundredths)	83.00%
[1]	Useful life of leased slots is based on the stated lease term.

Net_Income_Per_Share_Details

Net Income Per Share (Details) (USD $)	3 Months Ended									12 Months Ended
In Millions, except Per Share data, unless otherwise specified	Dec. 31, 2014		Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
NUMERATOR:
Net income	$190		$329	$465	$152	$212	$259	$224	$59	$1,136	$754	$421
Incremental income effect of interest on 5.25% convertible notes										4	3	3
Net income after assumed conversion										$1,140	$757	$424
DENOMINATOR:
Weighted-average shares outstanding, basic										687	710	750
Dilutive effect of Employee stock options and restricted stock units										3	2	1
Dilutive effect of 5.25% convertible notes										6	6	6
Adjusted weighted-average shares outstanding, diluted										696	718	757
NET INCOME PER SHARE:
Basic (in dollars per share)	$0.28	[1]	$0.48	$0.67	$0.22	$0.30	$0.37	$0.31	$0.08	$1.65	$1.06	$0.56
Diluted (in dollars per share)	$0.28	[1]	$0.48	$0.67	$0.22	$0.30	$0.37	$0.31	$0.08	$1.64	$1.05	$0.56
Stock Options
Potentially dilutive amounts excluded from calculations:
Potentially dilutive amounts excluded from calculations:										0	9	35
[1]	Includes a change in estimate, recorded on a prospective basis, effective October 1, 2014, which increased Passenger revenues by approximately $55 million and increased both Basic and Diluted net income per share by $.04. See Note 1 for further detail.

Net_Income_Per_Share_Parenthet

Net Income Per Share Parenthetical (Details) (Convertible Debt, 5.25% Convertible Senior Notes due 2016)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Convertible Debt | 5.25% Convertible Senior Notes due 2016
Debt Instrument [Line Items]
Interest rate stated in the debt agreement (in hundredths)	5.25%	5.25%	5.25%

Commitments_and_Contingencies_1

Commitments and Contingencies (Details) (USD $)	12 Months Ended				3 Months Ended
	Dec. 31, 2014		Dec. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Dec. 31, 2010
	aircraft
Airport Project [Line Items]
Assets constructed for others	$621,000,000		$453,000,000
Depreciation and amortization	938,000,000		867,000,000	844,000,000
Long-term Purchase Commitment [Line Items]
Firm - 737NG 700 (in units)	56	[1]
Firm - 737NG 800 (in units)	19
Options - 737NG (in units)	35
Additional - 700 A/C (in units)	20
Firm - 737MAX (in units)	30
Firm - 738MAX (in units)	170	[2]
Options - 737MAX (in units)	191
Total	521
Aircraft
Long-term Purchase Commitment [Line Items]
Committed expenditures, 2015	836,000,000
Committed expenditures, 2016	1,200,000,000
Committed expenditures, 2017	1,200,000,000
Committed expenditures, 2018	1,000,000,000
Committed expenditures, 2019	1,100,000,000
Committed expenditures, 2020 and beyond	5,700,000,000
2015
Long-term Purchase Commitment [Line Items]
Firm - 737NG 700 (in units)	0
Firm - 737NG 800 (in units)	19
Options - 737NG (in units)	0
Additional - 700 A/C (in units)	16
Firm - 737MAX (in units)	0
Firm - 738MAX (in units)	0
Options - 737MAX (in units)	0
Total	35
2016
Long-term Purchase Commitment [Line Items]
Firm - 737NG 700 (in units)	31
Firm - 737NG 800 (in units)	0
Options - 737NG (in units)	11
Additional - 700 A/C (in units)	4
Firm - 737MAX (in units)	0
Firm - 738MAX (in units)	0
Options - 737MAX (in units)	0
Total	46
2017
Long-term Purchase Commitment [Line Items]
Firm - 737NG 700 (in units)	15
Firm - 737NG 800 (in units)	0
Options - 737NG (in units)	12
Additional - 700 A/C (in units)	0
Firm - 737MAX (in units)	0
Firm - 738MAX (in units)	14
Options - 737MAX (in units)	0
Total	41
2018
Long-term Purchase Commitment [Line Items]
Firm - 737NG 700 (in units)	10
Firm - 737NG 800 (in units)	0
Options - 737NG (in units)	12
Additional - 700 A/C (in units)	0
Firm - 737MAX (in units)	0
Firm - 738MAX (in units)	13
Options - 737MAX (in units)	0
Total	35
2019
Long-term Purchase Commitment [Line Items]
Firm - 737NG 700 (in units)	0
Firm - 737NG 800 (in units)	0
Options - 737NG (in units)	0
Additional - 700 A/C (in units)	0
Firm - 737MAX (in units)	15
Firm - 738MAX (in units)	10
Options - 737MAX (in units)	0
Total	25
2020
Long-term Purchase Commitment [Line Items]
Firm - 737NG 700 (in units)	0
Firm - 737NG 800 (in units)	0
Options - 737NG (in units)	0
Additional - 700 A/C (in units)	0
Firm - 737MAX (in units)	14
Firm - 738MAX (in units)	22
Options - 737MAX (in units)	0
Total	36
2021
Long-term Purchase Commitment [Line Items]
Firm - 737NG 700 (in units)	0
Firm - 737NG 800 (in units)	0
Options - 737NG (in units)	0
Additional - 700 A/C (in units)	0
Firm - 737MAX (in units)	1
Firm - 738MAX (in units)	33
Options - 737MAX (in units)	18
Total	52
2022
Long-term Purchase Commitment [Line Items]
Firm - 737NG 700 (in units)	0
Firm - 737NG 800 (in units)	0
Options - 737NG (in units)	0
Additional - 700 A/C (in units)	0
Firm - 737MAX (in units)	0
Firm - 738MAX (in units)	30
Options - 737MAX (in units)	19
Total	49
2023
Long-term Purchase Commitment [Line Items]
Firm - 737NG 700 (in units)	0
Firm - 737NG 800 (in units)	0
Options - 737NG (in units)	0
Additional - 700 A/C (in units)	0
Firm - 737MAX (in units)	0
Firm - 738MAX (in units)	24
Options - 737MAX (in units)	23
Total	47
2024
Long-term Purchase Commitment [Line Items]
Firm - 737NG 700 (in units)	0
Firm - 737NG 800 (in units)	0
Options - 737NG (in units)	0
Additional - 700 A/C (in units)	0
Firm - 737MAX (in units)	0
Firm - 738MAX (in units)	24
Options - 737MAX (in units)	23
Total	47
2025
Long-term Purchase Commitment [Line Items]
Firm - 737NG 700 (in units)	0
Firm - 737NG 800 (in units)	0
Options - 737NG (in units)	0
Additional - 700 A/C (in units)	0
Firm - 737MAX (in units)	0
Firm - 738MAX (in units)	0
Options - 737MAX (in units)	36
Total	36
2026
Long-term Purchase Commitment [Line Items]
Firm - 737NG 700 (in units)	0
Firm - 737NG 800 (in units)	0
Options - 737NG (in units)	0
Additional - 700 A/C (in units)	0
Firm - 737MAX (in units)	0
Firm - 738MAX (in units)	0
Options - 737MAX (in units)	36
Total	36
2027
Long-term Purchase Commitment [Line Items]
Firm - 737NG 700 (in units)	0
Firm - 737NG 800 (in units)	0
Options - 737NG (in units)	0
Additional - 700 A/C (in units)	0
Firm - 737MAX (in units)	0
Firm - 738MAX (in units)	0
Options - 737MAX (in units)	36
Total	36
LAX
Airport Project [Line Items]
Expected total airport modernization project cost	525,000,000
Assets constructed for others	52,000,000
FLL
Airport Project [Line Items]
Expected total airport modernization project cost	295,000,000
DAL
Airport Project [Line Items]
Expected total airport modernization project cost	519,000,000
Municipal bonds issued					146,000,000	310,000,000
Number of gates with rights to occupy after completion	16
Assets constructed for others	504,000,000
Airport construction obligation	501,000,000
Depreciation and amortization	20,000,000
Property, Plant, and Equipment Useful Life	27 years
Property Plant And Equipment Percentage Cost To Residual Value Minimum	17.00%
HOU
Airport Project [Line Items]
Expected total airport modernization project cost	156,000,000
Assets constructed for others	$64,000,000
B-737-800
Airport Project [Line Items]
Number of Aircrafts Purchased	33
B-737-700
Airport Project [Line Items]
Number of Aircrafts Purchased	11
Number of aircrafts leased	11
B737-300
Airport Project [Line Items]
Number of aircrafts retired from service	3
B737-500
Airport Project [Line Items]
Number of aircrafts retired from service	2
B-717-200
Airport Project [Line Items]
Number of aircrafts removed from active service	66
[1]	The Company has flexibility to substitute 737-800s in lieu of 737-700 firm orders.
[2]	The Company has flexibility to substitute MAX 7 in lieu of MAX 8 firm orders beginning in 2019.

Supplemental_Financial_Informa1

Supplemental Financial Information - Other Assets (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Other Assets [Abstract]
Derivative contracts	$13	$145
Intangible assets	363	166
Non-current investments	35	44
Other	123	175
Other assets	$534	$530

Supplemental_Financial_Informa2

Supplemental Financial Information - Accounts Payable (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Accounts Payable [Abstract]
Accounts payable trade	$123	$189
Salaries payable	160	156
Taxes payable	163	146
Aircraft maintenance payable	314	331
Fuel payable	85	102
Other payable	358	323
Accounts payable	$1,203	$1,247

Supplemental_Financial_Informa3

Supplemental Financial Information - Accrued Liabilities (Details) (USD $)	Dec. 31, 2014		Dec. 31, 2013
In Millions, unless otherwise specified
Supplemental Financial Data [Line Items]
Profitsharing and savings plans	$374		$244
Aircraft and other lease related obligations	159		173
Vacation pay	292		278
Health	84		73
Workers compensation	165		161
Property and other taxes	81		65
Other	236		223
Accrued liabilities	1,565		1,229
Fuel derivatives | Accrued Liabilities
Supplemental Financial Data [Line Items]
Derivative Contracts	$174	[1]	$12	[1]
[1]	The net amounts of derivative assets and liabilities are reconciled to the individual line item amounts presented in the Consolidated Balance Sheet in Note 5.

Supplemental_Financial_Informa4

Supplemental Financial Information - Other Non-Current Liabilities (Details) (USD $)	Dec. 31, 2014		Dec. 31, 2013
In Millions, unless otherwise specified
Other Liabilities, Noncurrent [Abstract]
Postretirement obligation	$169		$138
Non-current lease-related obligations	193		290
Other deferred compensation	174		163
Deferred gains from sale and leaseback of aircraft	53		65
Other	44		70
Other non-current liabilities	1,255		771
Other Noncurrent Liabilities
Other Liabilities, Noncurrent [Abstract]
Derivative contracts	622
Other Noncurrent Liabilities | Interest Rate Swap
Other Liabilities, Noncurrent [Abstract]
Derivative contracts	$61	[1]	$45	[1]
[1]	The net amounts of derivative assets and liabilities are reconciled to the individual line item amounts presented in the Consolidated Balance Sheet in Note 5.

Schedule_of_Longterm_Debt_Deta

Schedule of Long-term Debt (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2006	Oct. 31, 2009	Dec. 31, 2012	Feb. 28, 2005	Apr. 29, 2009	Jul. 01, 2009	6-May-08	Feb. 28, 1997
In Millions, unless otherwise specified
Debt Instrument [Line Items]
Total	$2,713	$2,842
Less current maturities	258	629
Less debt discount and issuance costs	21	22
Long-term debt less current maturities	2,434	2,191
Capital Lease Obligations
Debt Instrument [Line Items]
Total	199	56
5.25% Notes due 2014 | Unsecured Debt
Debt Instrument [Line Items]
Total	0	357
Interest rate stated in the debt agreement (in hundredths)	5.25%
5.75% Notes due 2016
Debt Instrument [Line Items]
Interest rate stated in the debt agreement (in hundredths)			5.75%
5.75% Notes due 2016 | Unsecured Debt
Debt Instrument [Line Items]
Total	313	320
Interest rate stated in the debt agreement (in hundredths)	5.75%
5.25% Convertible Senior Notes due 2016 | AirTran Airways
Debt Instrument [Line Items]
Interest rate stated in the debt agreement (in hundredths)				5.25%
5.25% Convertible Senior Notes due 2016 | Convertible Debt
Debt Instrument [Line Items]
Interest rate stated in the debt agreement (in hundredths)	5.25%	5.25%			5.25%
5.25% Convertible Senior Notes due 2016 | Convertible Debt | AirTran Airways
Debt Instrument [Line Items]
Total	113	115
Interest rate stated in the debt agreement (in hundredths)	5.25%
5.125% Notes due 2017
Debt Instrument [Line Items]
Interest rate stated in the debt agreement (in hundredths)						5.13%
5.125% Notes due 2017 | Unsecured Debt
Debt Instrument [Line Items]
Total	316	322
Interest rate stated in the debt agreement (in hundredths)	5.13%
Fixed-rate 717 Aircraft Notes payable through 2017 - 10.37% | Enhanced Equipment Trust Certificate | AirTran Airways
Debt Instrument [Line Items]
Total	0	41
Interest rate stated in the debt agreement (in hundredths)	10.37%
French Credit Agreements due 2018 - 1.06% | Notes Payable to Banks
Debt Instrument [Line Items]
Total	36	46
Interest rate stated in the debt agreement (in hundredths)	1.06%
Fixed-rate 737 Aircraft Notes payable through 2018 - 7.02% | Notes Payable to Banks | AirTran Airways
Debt Instrument [Line Items]
Total	24	30
Interest rate stated in the debt agreement (in hundredths)	7.02%
2.75% Unsecured Senior Notes Due 2019
Debt Instrument [Line Items]
Interest rate stated in the debt agreement (in hundredths)	2.75%
2.75% Unsecured Senior Notes Due 2019 | Unsecured Debt
Debt Instrument [Line Items]
Total	300	0
Interest rate stated in the debt agreement (in hundredths)	2.75%
Term Loan Agreement due 2019 - 6.315%
Debt Instrument [Line Items]
Interest rate stated in the debt agreement (in hundredths)							6.32%
Term Loan Agreement due 2019 - 6.315% | Notes Payable to Banks
Debt Instrument [Line Items]
Total	178	210
Interest rate stated in the debt agreement (in hundredths)	6.32%
Term Loan Agreement due 2019 - 6.84%
Debt Instrument [Line Items]
Interest rate stated in the debt agreement (in hundredths)								6.84%
Term Loan Agreement due 2019 - 6.84% | Notes Payable to Banks
Debt Instrument [Line Items]
Total	73	85
Interest rate stated in the debt agreement (in hundredths)	6.84%
Term Loan Agreement due 2020 - 5.223%
Debt Instrument [Line Items]
Interest rate stated in the debt agreement (in hundredths)									5.22%
Term Loan Agreement due 2020 - 5.223% | Notes Payable to Banks
Debt Instrument [Line Items]
Total	372	413
Interest rate stated in the debt agreement (in hundredths)	5.22%
Floating-rate 737 Aircraft Notes payable through 2020 | Notes Payable to Banks | AirTran Airways
Debt Instrument [Line Items]
Total	300	340
Pass Through Certificates due 2022 - 6.24% | Enhanced Equipment Trust Certificate
Debt Instrument [Line Items]
Total	355	371
Interest rate stated in the debt agreement (in hundredths)	6.24%
7.375% Debentures due 2027
Debt Instrument [Line Items]
Interest rate stated in the debt agreement (in hundredths)										7.38%
7.375% Debentures due 2027 | Unsecured Debt
Debt Instrument [Line Items]
Total	$134	$136
Interest rate stated in the debt agreement (in hundredths)	7.38%	7.38%

Longterm_Debt_Details

Long-term Debt (Details) (USD $)

12 Months Ended

1 Months Ended

12 Months Ended

0 Months Ended

3 Months Ended

0 Months Ended

Dec. 31, 2014

Oct. 31, 2009

Dec. 31, 2013

Apr. 29, 2009

6-May-08

Dec. 31, 2004

Feb. 28, 1997

Jul. 01, 2009

Oct. 03, 2007

Dec. 31, 2006

Feb. 28, 2005

Sep. 30, 2004

Jun. 30, 2014

Loans

Agreements

Mortgages

Mortgages

Mortgages

Mortgages

Debt Instrument [Line Items]

Letters of Credit Outstanding Amount

440,000,000

Net book value of assets pledged as collateral for the Company's secured borrowings, primarily aircraft and engines

2,000,000,000

Maximum additional number of assets pledged as collateral in case obligations related to fuel derivatives exceed certain thresholds

81

Net book value of additional assets pledged as collateral in case obligations related to fuel derivatives exceed certain thresholds

2,000,000,000

Long-term Debt, by Maturity [Abstract]

2015

182,000,000

2016

610,000,000

2017

520,000,000

2018

264,000,000

2019

514,000,000

Thereafter

551,000,000

AirTran Airways

Debt Instrument [Line Items]

Number of mortgages on secured aircraft

22

AirTran Airways | Interest rate derivatives

Debt Instrument [Line Items]

Notional amount

243,000,000

AirTran Airways | Maximum | Interest rate derivatives

Debt Instrument [Line Items]

Interest rate stated in the debt agreement (in hundredths)

6.44%

Floating-rate 737 Aircraft Notes payable through 2020 | AirTran Airways

Debt Instrument [Line Items]

Number of mortgages on secured aircraft

19

Number of loans prepaid during period

8

Weighted average interest rate

1.66%

Fixed-rate 737 Aircraft Notes payable through 2018 - 7.02% | AirTran Airways

Debt Instrument [Line Items]

Weighted average interest rate

7.02%

5.25% Convertible Senior Notes due 2016

Debt Instrument [Line Items]

Conversion ratio

53.7747

Conversion price

$615.16

5.25% Convertible Senior Notes due 2016 | AirTran Airways

Debt Instrument [Line Items]

Face amount of debt

115,000,000

Interest rate stated in the debt agreement (in hundredths)

5.25%

Conversion ratio

167.5224

Extinguishment of debt amount

5,000,000

Repurchase price percentage

100.00%

Conversion option, amount

35,000,000

Unamortized premium

10,000,000

5.25% Convertible Senior Notes due 2016 | Southwest Airlines

Debt Instrument [Line Items]

Cash set aside for conversion

68,000,000

2.75% Unsecured Senior Notes Due 2019

Debt Instrument [Line Items]

Face amount of debt

300,000,000

Interest rate stated in the debt agreement (in hundredths)

2.75%

Term Loan Agreement due 2019 - 6.84%

Debt Instrument [Line Items]

Number of mortgages on secured aircraft

5

Interest rate stated in the debt agreement (in hundredths)

6.84%

Term Loan Agreement due 2019 - 6.84% | Maximum

Debt Instrument [Line Items]

Face amount of debt

124,000,000

Term Loan Agreement due 2019 - 6.315%

Debt Instrument [Line Items]

Number of mortgages on secured aircraft

14

Interest rate stated in the debt agreement (in hundredths)

6.32%

Term Loan Agreement due 2019 - 6.315% | LIBOR

Debt Instrument [Line Items]

Spread on variable rate

3.30%

Term Loan Agreement due 2019 - 6.315% | Maximum

Debt Instrument [Line Items]

Face amount of debt

332,000,000

Term Loan Agreement due 2020 - 5.223%

Debt Instrument [Line Items]

Number of mortgages on secured aircraft

21

Face amount of debt

600,000,000

Interest rate stated in the debt agreement (in hundredths)

5.22%

Term Loan Agreement due 2020 - 5.223% | LIBOR

Debt Instrument [Line Items]

Spread on variable rate

0.95%

Pass Through Certificates due 2022 - 6.24%

Debt Instrument [Line Items]

Number of mortgages on secured aircraft

16

Face amount of debt

500,000,000

Pass Through Certificates due 2022 - 6.24% | Interest rate derivatives | Cash Flow Hedging

Debt Instrument [Line Items]

Notional amount

20,000,000

Pass Through Certificates Series A

Debt Instrument [Line Items]

Face amount of debt

412,000,000

Interest rate stated in the debt agreement (in hundredths)

6.15%

Pass Through Certificates Series B

Debt Instrument [Line Items]

Face amount of debt

88,000,000

Interest rate stated in the debt agreement (in hundredths)

6.65%

5.75% Notes due 2016

Debt Instrument [Line Items]

Face amount of debt

300,000,000

Interest rate stated in the debt agreement (in hundredths)

5.75%

5.125% Notes due 2017

Debt Instrument [Line Items]

Face amount of debt

300,000,000

Interest rate stated in the debt agreement (in hundredths)

5.13%

French Credit Agreements due 2018 - 1.06%

Debt Instrument [Line Items]

Number of mortgages on secured aircraft

4

Face amount of debt

112,000,000

Number of identical floating rate financing agreements entered into concurrently with French banking partnerships

4

Term

13 years 0 months 0 days

French Credit Agreements due 2018 - 1.06% | LIBOR

Debt Instrument [Line Items]

Spread on variable rate

-45.00%

5.25% Notes due 2014

Debt Instrument [Line Items]

Face amount of debt

350,000,000

7.375% Debentures due 2027

Debt Instrument [Line Items]

Face amount of debt

100,000,000

Interest rate stated in the debt agreement (in hundredths)

7.38%

7.375% Debentures due 2027 | Treasury Rate

Debt Instrument [Line Items]

Spread on variable rate

20.00%

Enhanced Equipment Trust Certificate | Fixed-rate 717 Aircraft Notes payable through 2017 - 10.37% | AirTran Airways

Debt Instrument [Line Items]

Long-term Debt, Prepayment

7,000,000

35,000,000

Make Whole Penalty on Debt Extinguishment

6,000,000

Interest rate stated in the debt agreement (in hundredths)

10.37%

Unamortized premium

$5,000,000

Enhanced Equipment Trust Certificate | Pass Through Certificates due 2022 - 6.24%

Debt Instrument [Line Items]

Interest rate stated in the debt agreement (in hundredths)

6.24%

Leases_Details

Leases (Details) (USD $)	3 Months Ended	12 Months Ended					3 Months Ended
	Dec. 31, 2013	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012	Dec. 31, 2014	Jun. 30, 2014	Sep. 30, 2012	Jul. 09, 2012
	CapitalLeases	CapitalLeases		CapitalLeases			aircraft			aircraft
	aircraft	aircraft		aircraft
Capital Leases, Balance Sheet, Assets by Major Class, Net [Abstract]
Flight equipment	$69,000,000	$214,000,000		$69,000,000			$214,000,000
Less: accumulated amortization	12,000,000	22,000,000		12,000,000			22,000,000
Total	57,000,000	192,000,000		57,000,000			192,000,000
Capital leases
2015		33,000,000					33,000,000
2016		42,000,000					42,000,000
2017		45,000,000					45,000,000
2018		44,000,000					44,000,000
2019		43,000,000					43,000,000
Thereafter		202,000,000					202,000,000
Total minimum lease payments		409,000,000					409,000,000
Less amount representing interest		75,000,000					75,000,000
Present value of minimum lease payments		334,000,000					334,000,000
Less current portion		23,000,000					23,000,000
Long-term portion		311,000,000					311,000,000
Facility Operating leases
2015		753,000,000					753,000,000
2016		715,000,000					715,000,000
2017		671,000,000					671,000,000
2018		573,000,000					573,000,000
2019		502,000,000					502,000,000
Thereafter		1,802,000,000					1,802,000,000
Total minimum lease payments		5,016,000,000					5,016,000,000
Subleases
2015		-93,000,000					-93,000,000
2016		-103,000,000					-103,000,000
2017		-103,000,000					-103,000,000
2018		-102,000,000					-102,000,000
2019		-97,000,000					-97,000,000
Thereafter		-144,000,000					-144,000,000
Total minimum lease payments		-642,000,000					-642,000,000
Operating leases, net
2015		684,000,000					684,000,000
2016		636,000,000					636,000,000
2017		592,000,000					592,000,000
2018		496,000,000					496,000,000
2019		430,000,000					430,000,000
Thereafter		2,317,000,000					2,317,000,000
Total minimum lease payments		5,155,000,000					5,155,000,000
Capital Leased Assets [Line Items]
Number of capital leased assets	4	16		4			16
Rental expense for operating leases		931,000,000		997,000,000		943,000,000
Number of operating leased assets		174					174
Number of aircraft sold in sale and leaseback transaction	2			2
Sales Leaseback Transaction Gross Proceeds	12,000,000
Leaseback Period	11 years
Number of aircraft expected to be converted to sublease per month		3					3
Minimum
Capital Leased Assets [Line Items]
Renewal term		1 year
Maximum
Capital Leased Assets [Line Items]
Renewal term		5 years
B-717-200
Capital Leased Assets [Line Items]
Number of capital leased assets										2
Number of operating leased assets										76
Number of aircrafts subleased										88
Number of aircraft delivered to sublessee		52					52
Number of owned assets										10
Lease terms for owned aircraft							7 years
Contingent rental payment due		0					0
Residual value of leased properties		0					0
Estimated Loss On Sublease									137,000,000
Sublease transaction costs		86,000,000	[1]	12,000,000	[1]
Sublease Obligations	122,000,000	63,000,000		122,000,000		128,000,000	63,000,000
Interest expense related to accretion		-5,000,000		-6,000,000
Additional Estimated Loss on Sublease		22,000,000						22,000,000
Grounding Loss on Sublease		9,000,000
B-717-200 | Minimum
Capital Leased Assets [Line Items]
Sublease terms							3 years
B-717-200 | Maximum
Capital Leased Assets [Line Items]
Sublease terms							9 years
Love Field Airport
Facility Operating leases
2015		24,000,000					24,000,000
2016		24,000,000					24,000,000
2017		24,000,000					24,000,000
2018		25,000,000					25,000,000
2019		25,000,000					25,000,000
Thereafter		659,000,000					659,000,000
Total minimum lease payments		$781,000,000					$781,000,000
[1]	Includes lease conversion cost payments

LEASES_Sublease_Table_Details

LEASES Sublease Table (Details) (B-717-200, USD $)	3 Months Ended	12 Months Ended
In Millions, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
B-717-200
B717 Sublease Liability [Line Items]
Sublease Obligations		$63		$122		$128
Interest Expense, Accretion		5		6
Sublease Transaction Costs		-86	[1]	-12	[1]
Additional Estimated Loss on Sublease	$22	$22
[1]	Includes lease conversion cost payments

Common_Stock_Details

Common Stock (Details)	Dec. 31, 2014
In Millions, unless otherwise specified
Equity [Abstract]
Common stock reserved for issuance pursuant to Employee stock benefit plans (in shares)	47
Common stock reserved for issuance and not granted pursuant to Employee stock benefit plans (in shares)	20

Stock_Plans_Details

Stock Plans (Details) (USD $)	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013	Dec. 31, 2012
Employee service share based compensation aggregate disclosures [Abstract]
Share based compensation cost	$21,000,000		$18,000,000	$16,000,000
Employee Service Share-based Compensation, Tax Benefit from Compensation Expense	0
Total unrecognized compensation cost related to share-based compensation arrangements	33,000,000
Weighted average period of time over which unrecognized compensation cost is to be recognized (years)	1 year 1 month 12 days
The remaining number of RSU's or stock options that may be issued (in shares)	20,000,000
Additional disclosures for all plans for the period [Abstract]
Aggregate intrinsic value of options exercised for all plans during the period	75,000,000		22,000,000	1,000,000
Total fair value of shares vested during the period	15,000,000		16,000,000	13,000,000
Employee stock purchase plan [Abstract]
The remaining balance of shares originally authorized for issue under the employee stock purchase plan (in shares)	11,000,000
The percentage of market value at which shares may be issued to participating employees (in hundredths)	90.00%
The number of shares issued to participants under the plan during the period	792,000		1,500,000	2,200,000
The weighted average fair value of each purchase right under the employee stock purchase plan (in dollars per share)	$23.17		$12.03	$8.01
The discount percentage off the market value for the employee stock purchase plan (in hundredths)	10.00%
The aggregate cost of the discount from the market value on shares issued to employees at the end of each monthly purchase period	2.68		1.34	0.89
Three Year vesting
Employee service share based compensation aggregate disclosures [Abstract]
Vesting periods for plans	3 years 0 months 0 days
Five Year vesting
Employee service share based compensation aggregate disclosures [Abstract]
Vesting periods for plans	5 years 0 months 0 days
Ten Year vesting
Employee service share based compensation aggregate disclosures [Abstract]
Vesting periods for plans	10 years 0 months 0 days
Board of Directors
Employee service share based compensation aggregate disclosures [Abstract]
Non-option equity instruments granted (in shares)	36,000		63,000	82,000
Weighted average price of non-option equity instruments granted	$24.91		$14.34	$8.21
RSUs
Employee service share based compensation aggregate disclosures [Abstract]
Vesting periods for plans			3 years
The remaining number of RSU's or stock options that may be issued (in shares)			10,000,000
Units (000)
Outstanding RSU's - beginning balance (in shares)	2,584,000		2,876,000	1,640,000
Granted (in shares)	834,000	[1]	1,139,000	1,939,000
Vested (in shares)	-1,239,000		-1,263,000	-644,000
Surrendered (in shares)	-102,000		-168,000	-59,000
Outstanding RSU's - ending balance (in shares)	2,077,000		2,584,000	2,876,000
Wtd. Average Fair Value
Weighted average grant date fair value RSU's - beginning balance (in dollars per share)	$11.38		$9.57	$12.27
Weighted average grant date fair value RSU's - granted (in dollars per share)	$24.93		$14.34	$8.21
Weighted average grant date fair value RSU's - vested (in dollars per share)	$11.05		$10.24	$12.27
Weighted average grant date fair value RSU's - surrendered (in dollars per share)	$13.18		$9.11	$10.54
Weighted average grant date fair value RSU's - period end (in dollars per share)	$16.92		$11.38	$9.57
Performance Shares
Units (000)
Granted (in shares)			198,000
Stock Options
Options (000)
Outstanding - beginning balance (in shares)	9,161,000		18,910,000	47,324,000
Granted (in shares)	0		0	6,000
Exercised (in shares)	-6,636,000		-6,633,000	-573,000
Surrendered (in shares)	-48,000		-3,116,000	-27,847,000
Outstanding - ending balance (in shares)	2,477,000		9,161,000	18,910,000
Wtd. average exercise price
Weighted average exercise price - beginning balance (in dollars per share)	$14.58		$14.19	$14.51
Weighted average exercise price - granted (in dollars per share)	$0		$0	$9
Weighted average exercise price - exercised	$14.36		$13.31	$8
Weighted average exercise price - surrendered (in dollars per share)	$15.74		$14.94	$14.85
Weighted average exercise price - ending balance (in dollars per share)	$15.17		$14.58	$14.19
Weighted average remaining contractual term - period end (in years)	1 year 7 months 13 days
Aggregate intrinsic value - outstanding - period end	67,000,000
Stock options, vested and expected to vest [Abstract]
Vested or expected to vest, outstanding number (in shares)	2,473,000
Exercisable, outstanding number (in shares)	2,308,000
Weighted average exercise price - vested or expected to vest (in dollars per share)	$15.16
Weighted average exercise price - exercisable (in dollars per share)	$15.05
Weighted average remaining contractual term - vested or expected to vest - period end (in years)	1 year 7 months 16 days
Weighted average remaining contractual term - exercisable - period end (in years)	1 year 8 months 1 day
Aggregate intrinsic value - vested or expected to vest - period end	67,000,000
Aggregate intrinsic value - exercisable - period end	$63,000,000
Other Employee Plans
Employee service share based compensation aggregate disclosures [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period	10 years
Minimum | Performance Shares
Employee service share based compensation aggregate disclosures [Abstract]
Percentage of PBRSUs to be granted	0.00%
Performance Target			12.00%
Minimum | Collective Bargaining Plans
Employee service share based compensation aggregate disclosures [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period	6 years
Maximum | Performance Shares
Employee service share based compensation aggregate disclosures [Abstract]
Percentage of PBRSUs to be granted	200.00%
Performance Target			20.00%
Maximum | Collective Bargaining Plans
Employee service share based compensation aggregate disclosures [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period	12 years
[1]	Includes 198 thousand shares of PBRSUs

Financial_Derivative_Instrumen1

Financial Derivative Instruments Narrative (Details) (USD $)	12 Months Ended					6 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012	Dec. 31, 2013		6-May-08	Apr. 29, 2009	Feb. 28, 1997	Dec. 31, 2006
Derivative [Line Items]
Percent of fuel consumption hedged	34.00%
Premiums paid for fuel derivative contracts	$62,000,000		$60,000,000		$36,000,000
Current Unrealized Net Gains in OCI	219,000,000
Proceeds from termination of interest rate derivative instrument	0		0		38,000,000
Maximum sum of derivatives of counterparty to be included in other (less than $20 million)	25,000,000
Cash collateral provided as a percentage of derivative contract value (in hundredths)	100.00%
Derivative Asset, Fair Value, Gross Asset	1,360,000,000	[1]	503,000,000	[1]		503,000,000	[1]
Derivative Liability, Fair Value, Gross Liability	2,409,000,000	[1]	380,000,000	[1]		380,000,000	[1]
Derivative, Gain on Settlement	56,000,000
Amount paid for purchases and sales of offsetting derivative instruments	217,000,000
Term Loan Agreement due 2020 - 5.223%
Derivative [Line Items]
Face amount of debt								600,000,000
Interest rate stated in the debt agreement (in hundredths)								5.22%
Term Loan Agreement due 2019 - 6.315%
Derivative [Line Items]
Interest rate stated in the debt agreement (in hundredths)									6.32%
Term Loan Agreement due 2019 - 6.315% | Maximum
Derivative [Line Items]
Face amount of debt									332,000,000
7.375% Debentures due 2027
Derivative [Line Items]
Face amount of debt										100,000,000
Interest rate stated in the debt agreement (in hundredths)										7.38%
2.75% Unsecured Senior Notes Due 2019
Derivative [Line Items]
Face amount of debt	300,000,000
Interest rate stated in the debt agreement (in hundredths)	2.75%
5.75% Notes due 2016
Derivative [Line Items]
Face amount of debt											300,000,000
Interest rate stated in the debt agreement (in hundredths)											5.75%
Notes Payable to Banks | Term Loan Agreement due 2020 - 5.223%
Derivative [Line Items]
Face amount of debt	600,000,000
Interest rate stated in the debt agreement (in hundredths)	5.22%
Notes Payable to Banks | Term Loan Agreement due 2019 - 6.315%
Derivative [Line Items]
Face amount of debt	332,000,000
Interest rate stated in the debt agreement (in hundredths)	6.32%
Unsecured Debt | 7.375% Debentures due 2027
Derivative [Line Items]
Face amount of debt					100,000,000
Interest rate stated in the debt agreement (in hundredths)	7.38%		7.38%			7.38%
Unsecured Debt | 2.75% Unsecured Senior Notes Due 2019
Derivative [Line Items]
Face amount of debt	300,000,000
Interest rate stated in the debt agreement (in hundredths)	2.75%
Average Floating Rate	1.23%
Unsecured Debt | 5.75% Notes due 2016
Derivative [Line Items]
Face amount of debt	300,000,000
Interest rate stated in the debt agreement (in hundredths)	5.75%
Average Floating Rate	2.51%
Fuel derivatives
Derivative [Line Items]
Gain (Loss) On Derivative Due To Loss Of Hedge Accounting	45,000,000					-15,000,000
Total collateral already posted aggregate fair value	266,000,000		0			0
Interest rate derivatives | AirTran Airways
Derivative [Line Items]
Notional amount	243,000,000
Interest rate derivatives | AirTran Airways | Minimum
Derivative [Line Items]
Interest rate stated in the debt agreement (in hundredths)	4.35%
Interest rate derivatives | AirTran Airways | Maximum
Derivative [Line Items]
Interest rate stated in the debt agreement (in hundredths)	6.44%
Designated as Hedging Instrument
Derivative [Line Items]
Derivative Asset, Fair Value, Gross Asset	13,000,000	[1]	303,000,000	[1]		303,000,000	[1]
Derivative Liability, Fair Value, Gross Liability	704,000,000	[1]	78,000,000	[1]		78,000,000	[1]
Other Assets | Designated as Hedging Instrument | Fuel derivatives
Derivative [Line Items]
Derivative Asset, Fair Value, Gross Asset	0	[1]	209,000,000	[1]		209,000,000	[1]
Derivative Liability, Fair Value, Gross Liability	0	[1]	1,000,000	[1]		1,000,000	[1]
Other Assets | Designated as Hedging Instrument | Interest rate derivatives
Derivative [Line Items]
Derivative Asset, Fair Value, Gross Asset	13,000,000	[1]	20,000,000	[1]		20,000,000	[1]
Derivative Liability, Fair Value, Gross Liability	0	[1]	0	[1]		0	[1]
Other Liabilities | Designated as Hedging Instrument | Interest rate derivatives
Derivative [Line Items]
Derivative Liability, Fair Value, Gross Liability	$61,000,000
[1]	Represents the position of each trade before consideration of offsetting positions with each counterparty and does not include the impact of cash collateral deposits provided to or received from counterparties. See discussion of credit risk and collateral following in this Note.

Financial_Derivative_Instrumen2

Financial Derivative Instruments - Fuel Hedging (Details)	Dec. 31, 2014
	gal
2015
Volume of Fuel Hedging [Line Items]
Fuel Hedged (in gallons)	0	[1]
2016
Volume of Fuel Hedging [Line Items]
Fuel Hedged (in gallons)	885,000,000	[2]
2017
Volume of Fuel Hedging [Line Items]
Fuel Hedged (in gallons)	757,000,000	[2]
2018
Volume of Fuel Hedging [Line Items]
Fuel Hedged (in gallons)	0	[1]
[1]	In response to the precipitous decline in oil and jet fuel prices during the second half of 2014, the Company took action to offset its 2015 and 2018 fuel derivative portfolios and is now effectively unhedged at current price levels. While the Company still holds derivative contracts as of December 31, 2014, that will settle during 2015 and 2018, the majority of the losses associated with those contracts are substantially locked in.B However, if market prices were to increase or decrease significantly related to the 2015 positions prior to these contracts settling, the losses incurred at settlement could be slightly lower or higher than currently expected amounts during that period.
[2]	Due to the types of derivatives utilized by the Company and different price levels of those contracts, these volumes represent the maximum economic hedge in place and may vary significantly as market prices fluctuate.

Financial_Derivative_Instrumen3

Financial Derivative Instruments - Fair Values by Balance Sheet Location (Details) (USD $)	Dec. 31, 2014		Dec. 31, 2013
In Millions, unless otherwise specified
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	$1,360	[1]	$503	[1]
Derivative Liability, Fair Value, Gross Liability	2,409	[1]	380	[1]
Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	13	[1]	303	[1]
Derivative Liability, Fair Value, Gross Liability	704	[1]	78	[1]
Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	1,347	[1]	200	[1]
Derivative Liability, Fair Value, Gross Liability	1,705	[1]	302	[1]
Fuel derivatives | Accrued Liabilities
Derivatives, Fair Value [Line Items]
Collateral Already Posted, Aggregate Fair Value	68		0
Due To Third Parties For Settled Fuel Contracts	16		0
Fuel derivatives | Accounts And Other Receivables
Derivatives, Fair Value [Line Items]
Receivable from third parties for settled fuel contracts - current	0		57
Fuel derivatives | Other Noncurrent Liabilities
Derivatives, Fair Value [Line Items]
Collateral Already Posted, Aggregate Fair Value	198		0
Fuel derivatives | Designated as Hedging Instrument | Prepaid expenses and other current assets
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	0	[1]	74	[1]
Derivative Liability, Fair Value, Gross Liability	0	[1]	0	[1]
Fuel derivatives | Designated as Hedging Instrument | Other Assets
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	0	[1]	209	[1]
Derivative Liability, Fair Value, Gross Liability	0	[1]	1	[1]
Fuel derivatives | Designated as Hedging Instrument | Other Noncurrent Liabilities
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	0	[1]	0	[1]
Derivative Liability, Fair Value, Gross Liability	643	[1]	0	[1]
Fuel derivatives | Not Designated as Hedging Instrument | Prepaid expenses and other current assets
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	0	[1]	175	[1]
Derivative Liability, Fair Value, Gross Liability	0	[1]	182	[1]
Fuel derivatives | Not Designated as Hedging Instrument | Other Assets
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	0	[1]	16	[1]
Derivative Liability, Fair Value, Gross Liability	0	[1]	99	[1]
Fuel derivatives | Not Designated as Hedging Instrument | Accrued Liabilities
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	1,190	[1]	9	[1]
Derivative Liability, Fair Value, Gross Liability	1,432	[1]	21	[1]
Fuel derivatives | Not Designated as Hedging Instrument | Other Noncurrent Liabilities
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	157	[1]	0	[1]
Derivative Liability, Fair Value, Gross Liability	273	[1]	0	[1]
Interest rate derivatives | Other Noncurrent Liabilities
Derivatives, Fair Value [Line Items]
Collateral Already Posted, Aggregate Fair Value	0		32
Interest rate derivatives | Designated as Hedging Instrument | Other Assets
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	13	[1]	20	[1]
Derivative Liability, Fair Value, Gross Liability	0	[1]	0	[1]
Interest rate derivatives | Designated as Hedging Instrument | Other Noncurrent Liabilities
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	0	[1]	0	[1]
Derivative Liability, Fair Value, Gross Liability	61	[1]	77	[1]
Interest rate derivatives | Designated as Hedging Instrument | Other Liabilities
Derivatives, Fair Value [Line Items]
Derivative Liability, Fair Value, Gross Liability	$61
[1]	Represents the position of each trade before consideration of offsetting positions with each counterparty and does not include the impact of cash collateral deposits provided to or received from counterparties. See discussion of credit risk and collateral following in this Note.

Financial_Derivative_Instrumen4

Financial Derivative Instruments - Offsetting of Derivative Assets (Details) (USD $)	Dec. 31, 2014		Dec. 31, 2013
In Millions, unless otherwise specified
Offsetting Assets [Line Items]
Net amounts of assets presented in the Balance Sheet	$13		$145
Fuel derivatives | Prepaid expenses and other current assets
Offsetting Assets [Line Items]
Gross amounts of recognized assets	0		249
Gross amounts offset in the Balance Sheet	0		-182
Net amounts of assets presented in the Balance Sheet	0		67
Fuel derivatives | Other Assets
Offsetting Assets [Line Items]
Gross amounts of recognized assets	0		225
Gross amounts offset in the Balance Sheet	0		-100
Net amounts of assets presented in the Balance Sheet	0	[1]	125	[1]
Fuel derivatives | Accrued Liabilities
Offsetting Assets [Line Items]
Gross amounts of recognized assets	1,258		9
Gross amounts offset in the Balance Sheet	-1,258		-9
Net amounts of assets presented in the Balance Sheet	0	[1]	0	[1]
Fuel derivatives | Other Noncurrent Liabilities
Offsetting Assets [Line Items]
Gross amounts of recognized assets	355		0
Gross amounts offset in the Balance Sheet	-355		0
Net amounts of assets presented in the Balance Sheet	0	[1]	0	[1]
Interest rate derivatives | Other Assets
Offsetting Assets [Line Items]
Gross amounts of recognized assets	13		20
Gross amounts offset in the Balance Sheet	0		0
Net amounts of assets presented in the Balance Sheet	$13	[1]	$20	[1]
[1]	The net amounts of derivative assets and liabilities are reconciled to the individual line item amounts presented in the Consolidated Balance Sheet in Note 5.

Financial_Derivative_Instrumen5

Financial Derivative Instruments - Offsetting of Derivative Liabilities (Details) (USD $)	Dec. 31, 2014		Dec. 31, 2013
In Millions, unless otherwise specified
Other Noncurrent Liabilities
Offsetting Liabilities [Line Items]
Net amounts of liabilities presented in the Balance Sheet	$622
Fuel derivatives | Prepaid expenses and other current assets
Offsetting Liabilities [Line Items]
Gross amounts of recognized liabilities	0		182
Gross amounts offset in the Balance Sheet	0		-182
Net amounts of liabilities presented in the Balance Sheet	0		0
Fuel derivatives | Other Assets
Offsetting Liabilities [Line Items]
Gross amounts of recognized liabilities	0		100
Gross amounts offset in the Balance Sheet	0		-100
Net amounts of liabilities presented in the Balance Sheet	0	[1]	0	[1]
Fuel derivatives | Accrued Liabilities
Offsetting Liabilities [Line Items]
Gross amounts of recognized liabilities	1,432		21
Gross amounts offset in the Balance Sheet	-1,258		-9
Net amounts of liabilities presented in the Balance Sheet	174	[1]	12	[1]
Fuel derivatives | Other Noncurrent Liabilities
Offsetting Liabilities [Line Items]
Gross amounts of recognized liabilities	916		0
Gross amounts offset in the Balance Sheet	-355		0
Net amounts of liabilities presented in the Balance Sheet	561	[1]	0	[1]
Interest rate derivatives | Other Noncurrent Liabilities
Offsetting Liabilities [Line Items]
Gross amounts of recognized liabilities	61		77
Gross amounts offset in the Balance Sheet	0		-32
Net amounts of liabilities presented in the Balance Sheet	$61	[1]	$45	[1]
[1]	The net amounts of derivative assets and liabilities are reconciled to the individual line item amounts presented in the Consolidated Balance Sheet in Note 5.

Financial_Derivative_Instrumen6

Financial Derivative Instruments - (Gain) Loss by Hedging Relationship (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013
Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
(Gain) loss recognized in AOCI on derivatives (effective portion)	$755		$38
(Gain) loss reclassified from AOCI into income (effective portion)(a)	36	[1]	121	[1]
(Gain) loss recognized in income on derivatives (ineffective portion)(b)	3	[2]	11	[2]
Fuel derivatives | Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
(Gain) loss recognized in AOCI on derivatives (effective portion)	749	[3]	52	[3]
(Gain) loss reclassified from AOCI into income (effective portion)(a)	22	[1],[3]	103	[1],[3]
(Gain) loss recognized in income on derivatives (ineffective portion)(b)	7	[2]	10	[2]
Fuel derivatives | Not Designated as Hedging Instrument | Other Nonoperating Income Expense
Derivative Instruments, Gain (Loss) [Line Items]
(Gain) loss recognized in income on derivatives	244		-100
Interest rate derivatives | Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
(Gain) loss recognized in AOCI on derivatives (effective portion)	6	[3]	-14	[3]
(Gain) loss reclassified from AOCI into income (effective portion)(a)	14	[1],[3]	18	[1],[3]
(Gain) loss recognized in income on derivatives (ineffective portion)(b)	($4)	[2]	$1	[2]
[1]	Amounts related to fuel derivative contracts and interest rate derivatives are included in Fuel and oil and Interest expense, respectively.
[2]	Amounts are included in Other (gains) losses, net.
[3]	Net of tax

Financial_Derivative_Instrumen7

Financial Derivative Instruments - Fair Values of Fuel Derivatives Amounts Posted as Collateral (Details) (USD $)	Dec. 31, 2014
In Millions, unless otherwise specified
Schedule Of Fair Values Of Fuel Derivatives Amounts Posted As Collateral And Collateral Posting Thresholds [Line Items]
Maximum Sum Of Derivatives Of Counterparty To Be Included In Other	$25
If credit rating is non-investment grade, fair value of fuel derivative level at which:
Cash Collateral Percent Of Fair Value Fuel Derivatives Contracts	100.00%
Letter of Credit Percent of Collateral	100.00%
Fuel derivatives
Schedule Of Fair Values Of Fuel Derivatives Amounts Posted As Collateral And Collateral Posting Thresholds [Line Items]
Fair value of fuel derivatives	-1,001
Aircraft collateral pledged to CP	-134
Letters of credit (LC)	-250
Counterparty A | Fuel derivatives
Schedule Of Fair Values Of Fuel Derivatives Amounts Posted As Collateral And Collateral Posting Thresholds [Line Items]
Fair value of fuel derivatives	-333
Cash collateral held by CP	-50
Aircraft collateral pledged to CP	-134
Letters of credit (LC)	-100
Counterparty B | Fuel derivatives
Schedule Of Fair Values Of Fuel Derivatives Amounts Posted As Collateral And Collateral Posting Thresholds [Line Items]
Fair value of fuel derivatives	-136
Cash collateral held by CP	-98
Aircraft collateral pledged to CP	0
Letters of credit (LC)	0
Counterparty C | Fuel derivatives
Schedule Of Fair Values Of Fuel Derivatives Amounts Posted As Collateral And Collateral Posting Thresholds [Line Items]
Fair value of fuel derivatives	-122
Cash collateral held by CP	-57
Aircraft collateral pledged to CP	0
Letters of credit (LC)	0
Counterparty D | Fuel derivatives
Schedule Of Fair Values Of Fuel Derivatives Amounts Posted As Collateral And Collateral Posting Thresholds [Line Items]
Fair value of fuel derivatives	-219
Cash collateral held by CP	0
Aircraft collateral pledged to CP	0
Letters of credit (LC)	-150
Counterparty E | Fuel derivatives
Schedule Of Fair Values Of Fuel Derivatives Amounts Posted As Collateral And Collateral Posting Thresholds [Line Items]
Fair value of fuel derivatives	-66
Cash collateral held by CP	-23
Aircraft collateral pledged to CP	0
Letters of credit (LC)	0
Counterparty F | Fuel derivatives
Schedule Of Fair Values Of Fuel Derivatives Amounts Posted As Collateral And Collateral Posting Thresholds [Line Items]
Fair value of fuel derivatives	-86
Cash collateral held by CP	-38
Aircraft collateral pledged to CP	0
Letters of credit (LC)	0
Counterparty Other | Fuel derivatives
Schedule Of Fair Values Of Fuel Derivatives Amounts Posted As Collateral And Collateral Posting Thresholds [Line Items]
Fair value of fuel derivatives	-39	[1]
Cash collateral held by CP	0	[1]
Aircraft collateral pledged to CP	0	[1]
Letters of credit (LC)	0	[1]
Minimum | Counterparty A | Fuel derivatives
Schedule Of Fair Values Of Fuel Derivatives Amounts Posted As Collateral And Collateral Posting Thresholds [Line Items]
Option to substitute LC for cash Threshold 1	-50	[2]
If credit rating is investment grade, fair value of fuel derivative level at which:
Fair value of fuel derivative levels at which cash is provided to CP Threshold 1	-50
Fair value of fuel derivative levels at which cash is provided to CP Threshold 2	-600
Fair value of fuel derivative level at which cash is received from CP	50
Fair value of fuel derivative levels at which aircraft or cash collateral is pledged to CP	-200	[2]
If credit rating is non-investment grade, fair value of fuel derivative level at which:
Fair value of fuel derivative levels at which cash is provided to CP Threshold 1	0
Fair value of fuel derivative levels at which cash is provided to CP Threshold 2	-600
Fair value of fuel derivative level at which cash is received from CP		[3]
Fair value of fuel derivative levels at which aircraft collateral is pledged to CP	-200
Minimum | Counterparty B | Fuel derivatives
Schedule Of Fair Values Of Fuel Derivatives Amounts Posted As Collateral And Collateral Posting Thresholds [Line Items]
Option to substitute LC for aircraft	-100	[2]
Option to substitute LC for cash Threshold 1	-500
If credit rating is investment grade, fair value of fuel derivative level at which:
Fair value of fuel derivative levels at which cash is provided to CP Threshold 1	-50
Fair value of fuel derivative levels at which cash is provided to CP Threshold 2	-500
Fair value of fuel derivative level at which cash is received from CP	150
Fair value of fuel derivative levels at which aircraft or cash collateral is pledged to CP	-100	[2]
If credit rating is non-investment grade, fair value of fuel derivative level at which:
Fair value of fuel derivative levels at which cash is provided to CP Threshold 1	0
Fair value of fuel derivative levels at which cash is provided to CP Threshold 2	-500
Fair value of fuel derivative level at which cash is received from CP		[3]
Fair value of fuel derivative levels at which aircraft collateral is pledged to CP	-100
Minimum | Counterparty C | Fuel derivatives
Schedule Of Fair Values Of Fuel Derivatives Amounts Posted As Collateral And Collateral Posting Thresholds [Line Items]
Option to substitute LC for cash Threshold 1	-100	[4]
If credit rating is investment grade, fair value of fuel derivative level at which:
Fair value of fuel derivative levels at which cash is provided to CP Threshold 1	-75
Fair value of fuel derivative level at which cash is received from CP	175	[5]
If credit rating is non-investment grade, fair value of fuel derivative level at which:
Fair value of fuel derivative levels at which cash is provided to CP Threshold 1		[3]
Fair value of fuel derivative level at which cash is received from CP		[3]
Minimum | Counterparty D | Fuel derivatives
Schedule Of Fair Values Of Fuel Derivatives Amounts Posted As Collateral And Collateral Posting Thresholds [Line Items]
Option to substitute LC for aircraft	-150	[2]
Option to substitute LC for cash Threshold 1	-75	[2]
Option to substitute LC for cash Threshold 2	-550	[2]
If credit rating is investment grade, fair value of fuel derivative level at which:
Fair value of fuel derivative levels at which cash is provided to CP Threshold 1	-75
Fair value of fuel derivative levels at which cash is provided to CP Threshold 2	-550
Fair value of fuel derivative level at which cash is received from CP	200
Fair value of fuel derivative levels at which aircraft or cash collateral is pledged to CP	-150	[2]
If credit rating is non-investment grade, fair value of fuel derivative level at which:
Fair value of fuel derivative levels at which cash is provided to CP Threshold 1	0
Fair value of fuel derivative levels at which cash is provided to CP Threshold 2	-550
Fair value of fuel derivative level at which cash is received from CP		[3]
Fair value of fuel derivative levels at which aircraft collateral is pledged to CP	-150
Minimum | Counterparty E | Fuel derivatives
If credit rating is investment grade, fair value of fuel derivative level at which:
Fair value of fuel derivative levels at which cash is provided to CP Threshold 1	-50
Fair value of fuel derivative level at which cash is received from CP	30
If credit rating is non-investment grade, fair value of fuel derivative level at which:
Fair value of fuel derivative levels at which cash is provided to CP Threshold 1		[3]
Fair value of fuel derivative level at which cash is received from CP		[3]
Minimum | Counterparty F | Fuel derivatives
If credit rating is investment grade, fair value of fuel derivative level at which:
Fair value of fuel derivative levels at which cash is provided to CP Threshold 1	-50
Fair value of fuel derivative level at which cash is received from CP	-50
If credit rating is non-investment grade, fair value of fuel derivative level at which:
Fair value of fuel derivative levels at which cash is provided to CP Threshold 1		[3]
Fair value of fuel derivative level at which cash is received from CP		[3]
Maximum | Counterparty A | Fuel derivatives
Schedule Of Fair Values Of Fuel Derivatives Amounts Posted As Collateral And Collateral Posting Thresholds [Line Items]
Option to substitute LC for aircraft	-400	[6]
Option to substitute LC for cash Threshold 1	-150	[2]
If credit rating is investment grade, fair value of fuel derivative level at which:
Fair value of fuel derivative levels at which cash is provided to CP Threshold 1	-200
Fair value of fuel derivative levels at which aircraft or cash collateral is pledged to CP	-600	[2]
If credit rating is non-investment grade, fair value of fuel derivative level at which:
Fair value of fuel derivative levels at which cash is provided to CP Threshold 1	-200
Fair value of fuel derivative levels at which aircraft collateral is pledged to CP	-600
Maximum | Counterparty B | Fuel derivatives
Schedule Of Fair Values Of Fuel Derivatives Amounts Posted As Collateral And Collateral Posting Thresholds [Line Items]
Option to substitute LC for aircraft	-500	[2]
If credit rating is investment grade, fair value of fuel derivative level at which:
Fair value of fuel derivative levels at which cash is provided to CP Threshold 1	-100
Fair value of fuel derivative levels at which aircraft or cash collateral is pledged to CP	-500	[2]
If credit rating is non-investment grade, fair value of fuel derivative level at which:
Fair value of fuel derivative levels at which cash is provided to CP Threshold 1	-100
Fair value of fuel derivative levels at which aircraft collateral is pledged to CP	-500
Maximum | Counterparty C | Fuel derivatives
Schedule Of Fair Values Of Fuel Derivatives Amounts Posted As Collateral And Collateral Posting Thresholds [Line Items]
Option to substitute LC for cash Threshold 1	-150	[4]
Maximum | Counterparty D | Fuel derivatives
Schedule Of Fair Values Of Fuel Derivatives Amounts Posted As Collateral And Collateral Posting Thresholds [Line Items]
Option to substitute LC for aircraft	-550	[2]
Option to substitute LC for cash Threshold 1	-150	[2]
If credit rating is investment grade, fair value of fuel derivative level at which:
Fair value of fuel derivative levels at which cash is provided to CP Threshold 1	-150
Fair value of fuel derivative levels at which aircraft or cash collateral is pledged to CP	-550	[2]
If credit rating is non-investment grade, fair value of fuel derivative level at which:
Fair value of fuel derivative levels at which cash is provided to CP Threshold 1	-150
Fair value of fuel derivative levels at which aircraft collateral is pledged to CP	-550
Maximum | Counterparty F | Fuel derivatives
Schedule Of Fair Values Of Fuel Derivatives Amounts Posted As Collateral And Collateral Posting Thresholds [Line Items]
Option to substitute LC for cash Threshold 1		[7]
[1]	Individual counterparties with fair value of fuel derivatives <$25 million.
[2]	The Company has the option of providing cash, letters of credit, or pledging aircraft as collateral.
[3]	Cash collateral is provided at 100 percent of fair value of fuel derivative contracts.
[4]	The Company has the option of providing cash or letters of credit as collateral.
[5]	Thresholds may vary based on changes in credit ratings within investment grade.
[6]	The Company has the option of providing letters of credit in addition to aircraft collateral if the appraised value of the aircraft does not meet the collateral requirements.
[7]	The Company has the option to substitute letters of credit for 100 percent of cash collateral requirement.

Fair_Value_Measurements_Narrat

Fair Value Measurements Narrative (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014
	Agreements
Fair Value Disclosures [Abstract]
Available-for-sale Securities, Fair Value Disclosure	$27
Debt agreements not publicly held	6

Fair_Value_Measurements_Measur

Fair Value Measurements - Measured on Recurring Basis (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Assets, Level 1 to Level 2 Transfers, Amount	$0		$0
Fair Value, Liabilities, Level 1 to Level 2 Transfers, Amount	0		0
Fair Value, Assets, Level 2 to Level 1 Transfers, Amount	0		0
Fair Value, Liabilities, Level 2 to Level 1 Transfers, Amount	0		0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers, Net	0		0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Transfers, Net	0		0
Fuel derivatives:
Derivative Asset, Fair Value, Gross Asset	1,360	[1]	503	[1]
Fuel derivatives:
Derivative Liability, Fair Value, Gross Liability	-2,409	[1]	-380	[1]
Fair Value, Measurements, Recurring | Period end date
Assets
Treasury bills	1,450		1,570
Interest rate derivatives (see Note 10)	13		20
Fuel derivatives:
Other available for sale securities	68		63
Total assets	4,443		3,757
Fuel derivatives:
Interest rate derivatives (see Note 10)	-61		-77
Deferred Compensation	-168		-158
Total Liabilities	-2,409		-380
Fair Value, Measurements, Recurring | Quoted prices in active markets for identical assets (Level 1)
Assets
Treasury bills	1,450		1,570
Interest rate derivatives (see Note 10)	0		0
Fuel derivatives:
Other available for sale securities	63		58
Total assets	2,623		2,620
Fuel derivatives:
Interest rate derivatives (see Note 10)	0		0
Deferred Compensation	-168		-158
Fair Value, Measurements, Recurring | Significant other observable inputs (Level 2)
Assets
Treasury bills	0		0
Interest rate derivatives (see Note 10)	13		20
Fuel derivatives:
Other available for sale securities	0		0
Total assets	896		626
Fuel derivatives:
Interest rate derivatives (see Note 10)	-61		-77
Deferred Compensation	0		0
Total Liabilities	-426		-85
Fair Value, Measurements, Recurring | Significant unobservable inputs (Level 3)
Assets
Treasury bills	0		0
Interest rate derivatives (see Note 10)	0		0
Fuel derivatives:
Other available for sale securities	5		5
Total assets	924		511
Fuel derivatives:
Interest rate derivatives (see Note 10)	0		0
Deferred Compensation	0		0
Total Liabilities	-1,983		-295
Cash Equivalents | Fair Value, Measurements, Recurring | Period end date
Assets
Cash equivalents	1,110	[2]	992	[2]
Cash Equivalents | Fair Value, Measurements, Recurring | Quoted prices in active markets for identical assets (Level 1)
Assets
Cash equivalents	1,110	[2]	992	[2]
Cash Equivalents | Fair Value, Measurements, Recurring | Significant other observable inputs (Level 2)
Assets
Cash equivalents	0	[2]	0	[2]
Cash Equivalents | Fair Value, Measurements, Recurring | Significant unobservable inputs (Level 3)
Assets
Cash equivalents	0	[2]	0	[2]
Commercial paper | Fair Value, Measurements, Recurring | Period end date
Assets
Cash equivalents	70		280
Commercial paper | Fair Value, Measurements, Recurring | Quoted prices in active markets for identical assets (Level 1)
Assets
Cash equivalents	0		0
Commercial paper | Fair Value, Measurements, Recurring | Significant other observable inputs (Level 2)
Assets
Cash equivalents	70		280
Commercial paper | Fair Value, Measurements, Recurring | Significant unobservable inputs (Level 3)
Assets
Cash equivalents	0		0
Certificates of deposit | Fair Value, Measurements, Recurring | Period end date
Assets
Cash equivalents	4		23
Certificates of deposit | Fair Value, Measurements, Recurring | Quoted prices in active markets for identical assets (Level 1)
Assets
Cash equivalents	0		0
Certificates of deposit | Fair Value, Measurements, Recurring | Significant other observable inputs (Level 2)
Assets
Cash equivalents	4		23
Certificates of deposit | Fair Value, Measurements, Recurring | Significant unobservable inputs (Level 3)
Assets
Cash equivalents	0		0
Eurodollar Time Deposits | Fair Value, Measurements, Recurring | Period end date
Assets
Cash equivalents	98		60
Eurodollar Time Deposits | Fair Value, Measurements, Recurring | Quoted prices in active markets for identical assets (Level 1)
Assets
Cash equivalents	0		0
Eurodollar Time Deposits | Fair Value, Measurements, Recurring | Significant other observable inputs (Level 2)
Assets
Cash equivalents	98		60
Eurodollar Time Deposits | Fair Value, Measurements, Recurring | Significant unobservable inputs (Level 3)
Assets
Cash equivalents	0		0
Certificates of deposit | Fair Value, Measurements, Recurring | Period end date
Assets
Investments	256		227
Certificates of deposit | Fair Value, Measurements, Recurring | Quoted prices in active markets for identical assets (Level 1)
Assets
Investments	0		0
Certificates of deposit | Fair Value, Measurements, Recurring | Significant other observable inputs (Level 2)
Assets
Investments	256		227
Certificates of deposit | Fair Value, Measurements, Recurring | Significant unobservable inputs (Level 3)
Assets
Investments	0		0
Auction rate securities | Fair Value, Measurements, Recurring | Period end date
Assets
Investments	27	[3]	39	[3]
Auction rate securities | Fair Value, Measurements, Recurring | Quoted prices in active markets for identical assets (Level 1)
Assets
Investments	0	[3]	0	[3]
Auction rate securities | Fair Value, Measurements, Recurring | Significant other observable inputs (Level 2)
Assets
Investments	0	[3]	0	[3]
Auction rate securities | Fair Value, Measurements, Recurring | Significant unobservable inputs (Level 3)
Assets
Investments	27	[3]	39	[3]
Swap | Fair Value, Measurements, Recurring | Period end date
Fuel derivatives:
Derivative Asset, Fair Value, Gross Asset	455	[4]	16	[5]
Fuel derivatives:
Derivative Asset, Fair Value, Gross Liability	-365	[4]	-8	[5]
Derivative Liability, Fair Value, Gross Liability			-21	[4]
Swap | Fair Value, Measurements, Recurring | Quoted prices in active markets for identical assets (Level 1)
Fuel derivatives:
Derivative Asset, Fair Value, Gross Asset	0	[4]	0	[5]
Fuel derivatives:
Derivative Asset, Fair Value, Gross Liability	0	[4]	0	[5]
Derivative Liability, Fair Value, Gross Liability			0	[4]
Swap | Fair Value, Measurements, Recurring | Significant other observable inputs (Level 2)
Fuel derivatives:
Derivative Asset, Fair Value, Gross Asset	455	[4]	16	[5]
Fuel derivatives:
Derivative Asset, Fair Value, Gross Liability	-365	[4]	-8	[5]
Swap | Fair Value, Measurements, Recurring | Significant unobservable inputs (Level 3)
Fuel derivatives:
Derivative Asset, Fair Value, Gross Asset	0	[4]	0	[5]
Fuel derivatives:
Derivative Asset, Fair Value, Gross Liability	0	[4]	0	[5]
Derivative Liability, Fair Value, Gross Liability			-21	[4]
Options Held | Fair Value, Measurements, Recurring | Period end date
Fuel derivatives:
Derivative Asset, Fair Value, Gross Asset			458	[5]
Derivative Liability, Fair Value, Gross Asset	892	[4]	9	[4]
Fuel derivatives:
Derivative Asset, Fair Value, Gross Liability			-274	[5]
Derivative Liability, Fair Value, Gross Liability	-1,983	[4]
Options Held | Fair Value, Measurements, Recurring | Quoted prices in active markets for identical assets (Level 1)
Fuel derivatives:
Derivative Asset, Fair Value, Gross Asset			0	[5]
Derivative Liability, Fair Value, Gross Asset	0	[4]	0	[4]
Fuel derivatives:
Derivative Asset, Fair Value, Gross Liability			0	[5]
Derivative Liability, Fair Value, Gross Liability	0	[4]
Options Held | Fair Value, Measurements, Recurring | Significant other observable inputs (Level 2)
Fuel derivatives:
Derivative Asset, Fair Value, Gross Asset			0	[5]
Derivative Liability, Fair Value, Gross Asset	0	[4]	0	[4]
Fuel derivatives:
Derivative Asset, Fair Value, Gross Liability			0	[5]
Derivative Liability, Fair Value, Gross Liability	0	[4]
Options Held | Fair Value, Measurements, Recurring | Significant unobservable inputs (Level 3)
Fuel derivatives:
Derivative Asset, Fair Value, Gross Asset			458	[5]
Derivative Liability, Fair Value, Gross Asset	892	[4]	9	[4]
Fuel derivatives:
Derivative Asset, Fair Value, Gross Liability			-274	[5]
Derivative Liability, Fair Value, Gross Liability	($1,983)	[4]
[1]	Represents the position of each trade before consideration of offsetting positions with each counterparty and does not include the impact of cash collateral deposits provided to or received from counterparties. See discussion of credit risk and collateral following in this Note.
[2]	Cash equivalents are primarily composed of money market investments.
[3]	Noncurrent investments are included in Other assets in the Consolidated Balance Sheet.
[4]	In the Consolidated Balance Sheet amounts are presented as a net liability. See Note 10.
[5]	In the Consolidated Balance Sheet amounts are presented as a net asset. See Note 10.

Fair_Value_Measurement_Fair_Va

Fair Value Measurement - Fair Value Assets and Liabilities Measured on Recurring Basis with Unobservable Inputs (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	$216		$260
Total gains or (losses) (realized or unrealized)
Included in earnings	-439		71
Included in other comprehensive income	-1,088		-104
Purchases	403		357
Sales	-170		-417
Settlements	19		49
Ending Balance	-1,059		216
The amount of total losses for the period included in earnings attributable to the change in unrealized gains or losses relating to assets still held at December 31, 2014	-450		86
Fuel derivatives
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	172		219
Total gains or (losses) (realized or unrealized)
Included in earnings	-439		71
Included in other comprehensive income	-1,091		-107
Purchases	403	[1]	357	[1]
Sales	-155	[1]	-417	[1]
Settlements	19		49
Ending Balance	-1,091		172
The amount of total losses for the period included in earnings attributable to the change in unrealized gains or losses relating to assets still held at December 31, 2014	-450		86
Auction rate securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	39	[2]	36
Total gains or (losses) (realized or unrealized)
Included in earnings	0		0
Included in other comprehensive income	3		3
Purchases	0		0
Sales	-15		0
Settlements	0		0
Ending Balance	27	[2]	39	[2]
The amount of total losses for the period included in earnings attributable to the change in unrealized gains or losses relating to assets still held at December 31, 2014	0		0
Other securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	5		5
Total gains or (losses) (realized or unrealized)
Included in earnings	0		0
Included in other comprehensive income	0		0
Purchases	0		0
Sales	0		0
Settlements	0		0
Ending Balance	5		5
The amount of total losses for the period included in earnings attributable to the change in unrealized gains or losses relating to assets still held at December 31, 2014	$0		$0
[1]	The purchase and sale of fuel derivatives are recorded gross based on the structure of the derivative instrument and whether a contract with multiple derivatives is purchased as a single instrument or separate instruments.
[2]	Included in Other assets in the Consolidated Balance Sheet.

Fair_Value_Measurements_Quanti

Fair Value Measurements - Quantitative Information about Level 3 Fair Value (Details)	12 Months Ended
	Dec. 31, 2014
Discounted Cash Flow | Illiquidity Premium | Auction rate securities
Quantitative Information About Level 3 [Line Items]
Fair Value Measurement Range, Minimum	3.00%
Fair Value Measurement Range, Maximum
Discounted Cash Flow | Counterparty Credit Spread | Auction rate securities
Quantitative Information About Level 3 [Line Items]
Fair Value Measurement Range, Minimum	1.00%
Fair Value Measurement Range, Maximum	2.00%
Discounted Cash Flow | Time To Principal Recovery | Auction rate securities
Quantitative Information About Level 3 [Line Items]
Fair Value Measurement Range, Minimum, Term	8 years
Fair Value Measurement Range, Maximum, Term
2015 | Option Model | Implied Volatility | Fuel derivatives
Quantitative Information About Level 3 [Line Items]
Fair Value Measurement Range, Minimum	23.00%
Fair Value Measurement Range, Maximum	47.00%
2016 | Option Model | Implied Volatility | Fuel derivatives
Quantitative Information About Level 3 [Line Items]
Fair Value Measurement Range, Minimum	24.00%
Fair Value Measurement Range, Maximum	36.00%
2017 | Option Model | Implied Volatility | Fuel derivatives
Quantitative Information About Level 3 [Line Items]
Fair Value Measurement Range, Minimum	19.00%
Fair Value Measurement Range, Maximum	30.00%
2018 | Option Model | Implied Volatility | Fuel derivatives
Quantitative Information About Level 3 [Line Items]
Fair Value Measurement Range, Minimum	25.00%
Fair Value Measurement Range, Maximum	27.00%

Fair_Value_Instruments_Carryin

Fair Value Instruments - Carrying and Estimated Fair Value of Debt (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2006	Dec. 31, 2012	Feb. 28, 2005	Apr. 29, 2009	Jul. 01, 2009	6-May-08	Feb. 28, 1997	Oct. 31, 2009
In Millions, unless otherwise specified
Debt Instrument [Line Items]
Debt and Capital Lease Obligations	$2,713	$2,842
5.75% Notes due 2016
Debt Instrument [Line Items]
Interest rate stated in the debt agreement (in hundredths)			5.75%
5.75% Notes due 2016 | Unsecured Debt
Debt Instrument [Line Items]
Debt and Capital Lease Obligations	313	320
Interest rate stated in the debt agreement (in hundredths)	5.75%
5.25% Convertible Senior Notes due 2016 | Convertible Debt
Debt Instrument [Line Items]
Interest rate stated in the debt agreement (in hundredths)	5.25%	5.25%		5.25%
5.125% Notes due 2017
Debt Instrument [Line Items]
Interest rate stated in the debt agreement (in hundredths)					5.13%
5.125% Notes due 2017 | Unsecured Debt
Debt Instrument [Line Items]
Debt and Capital Lease Obligations	316	322
Interest rate stated in the debt agreement (in hundredths)	5.13%
French Credit Agreements due 2018 - 1.06% | Notes Payable to Banks
Debt Instrument [Line Items]
Debt and Capital Lease Obligations	36	46
Interest rate stated in the debt agreement (in hundredths)	1.06%
2.75% Unsecured Senior Notes Due 2019
Debt Instrument [Line Items]
Interest rate stated in the debt agreement (in hundredths)	2.75%
2.75% Unsecured Senior Notes Due 2019 | Unsecured Debt
Debt Instrument [Line Items]
Debt and Capital Lease Obligations	300	0
Interest rate stated in the debt agreement (in hundredths)	2.75%
Term Loan Agreement due 2019 - 6.315%
Debt Instrument [Line Items]
Interest rate stated in the debt agreement (in hundredths)						6.32%
Term Loan Agreement due 2019 - 6.315% | Notes Payable to Banks
Debt Instrument [Line Items]
Debt and Capital Lease Obligations	178	210
Interest rate stated in the debt agreement (in hundredths)	6.32%
Term Loan Agreement due 2019 - 6.84%
Debt Instrument [Line Items]
Interest rate stated in the debt agreement (in hundredths)							6.84%
Term Loan Agreement due 2019 - 6.84% | Notes Payable to Banks
Debt Instrument [Line Items]
Debt and Capital Lease Obligations	73	85
Interest rate stated in the debt agreement (in hundredths)	6.84%
Term Loan Agreement due 2020 - 5.223%
Debt Instrument [Line Items]
Interest rate stated in the debt agreement (in hundredths)								5.22%
Term Loan Agreement due 2020 - 5.223% | Notes Payable to Banks
Debt Instrument [Line Items]
Debt and Capital Lease Obligations	372	413
Interest rate stated in the debt agreement (in hundredths)	5.22%
Pass Through Certificates due 2022 - 6.24% | Enhanced Equipment Trust Certificate
Debt Instrument [Line Items]
Debt and Capital Lease Obligations	355	371
Interest rate stated in the debt agreement (in hundredths)	6.24%
7.375% Debentures due 2027
Debt Instrument [Line Items]
Interest rate stated in the debt agreement (in hundredths)									7.38%
7.375% Debentures due 2027 | Unsecured Debt
Debt Instrument [Line Items]
Debt and Capital Lease Obligations	134	136
Interest rate stated in the debt agreement (in hundredths)	7.38%	7.38%
Level 2 | 5.75% Notes due 2016 | Unsecured Debt
Debt Instrument [Line Items]
Notes Payable, Fair Value	335
Level 2 | 5.25% Convertible Senior Notes due 2016 | Convertible Debt
Debt Instrument [Line Items]
Notes Payable, Fair Value	318
Level 2 | 5.125% Notes due 2017 | Unsecured Debt
Debt Instrument [Line Items]
Notes Payable, Fair Value	338
Level 2 | 2.75% Unsecured Senior Notes Due 2019 | Unsecured Debt
Debt Instrument [Line Items]
Notes Payable, Fair Value	304
Level 2 | Pass Through Certificates due 2022 - 6.24% | Enhanced Equipment Trust Certificate
Debt Instrument [Line Items]
Notes Payable, Fair Value	410
Level 2 | 7.375% Debentures due 2027 | Unsecured Debt
Debt Instrument [Line Items]
Loans Payable, Fair Value	160
Level 3 | French Credit Agreements due 2018 - 1.06% | Notes Payable to Banks
Debt Instrument [Line Items]
Notes Payable, Fair Value	36
Level 3 | Fixed-rate 737 Aircraft Notes payable through 2018 - 7.02% | Notes Payable to Banks
Debt Instrument [Line Items]
Notes Payable, Fair Value	25
Level 3 | Term Loan Agreement due 2019 - 6.315% | Notes Payable to Banks
Debt Instrument [Line Items]
Loans Payable, Fair Value	178
Level 3 | Term Loan Agreement due 2019 - 6.84% | Notes Payable to Banks
Debt Instrument [Line Items]
Loans Payable, Fair Value	79
Level 3 | Term Loan Agreement due 2020 - 5.223% | Notes Payable to Banks
Debt Instrument [Line Items]
Loans Payable, Fair Value	367
Level 3 | Floating-rate 737 Aircraft Notes payable through 2020 | Notes Payable to Banks
Debt Instrument [Line Items]
Notes Payable, Fair Value	293
AirTran Airways | 5.25% Convertible Senior Notes due 2016
Debt Instrument [Line Items]
Interest rate stated in the debt agreement (in hundredths)										5.25%
AirTran Airways | 5.25% Convertible Senior Notes due 2016 | Convertible Debt
Debt Instrument [Line Items]
Debt and Capital Lease Obligations	113	115
Interest rate stated in the debt agreement (in hundredths)	5.25%
AirTran Airways | Fixed-rate 717 Aircraft Notes payable through 2017 - 10.37% | Enhanced Equipment Trust Certificate
Debt Instrument [Line Items]
Debt and Capital Lease Obligations	0	41
Interest rate stated in the debt agreement (in hundredths)	10.37%
AirTran Airways | Fixed-rate 737 Aircraft Notes payable through 2018 - 7.02% | Notes Payable to Banks
Debt Instrument [Line Items]
Debt and Capital Lease Obligations	24	30
Interest rate stated in the debt agreement (in hundredths)	7.02%
AirTran Airways | Floating-rate 737 Aircraft Notes payable through 2020 | Notes Payable to Banks
Debt Instrument [Line Items]
Debt and Capital Lease Obligations	$300	$340

Accumulated_Other_Comprehensiv1

Accumulated Other Comprehensive Income (Loss) (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Accumulated Other Comprehensive Income Loss Net Of Tax [Roll Forward]
Balance at end of period	($738)	($3)
Fuel derivatives
Accumulated Other Comprehensive Income Loss Net Of Tax [Roll Forward]
Balance at beginning of period	-20	-103
Changes in fair value	-1,191	-82
Reclassification to earnings	34	165
Balance at end of period	-1,177	-20
Interest rate derivatives
Accumulated Other Comprehensive Income Loss Net Of Tax [Roll Forward]
Balance at beginning of period	-58	-108
Changes in fair value	-10	22
Reclassification to earnings	23	28
Balance at end of period	-45	-58
Defined benefit plan items
Accumulated Other Comprehensive Income Loss Net Of Tax [Roll Forward]
Balance at beginning of period	65	26
Changes in fair value	-24	39
Reclassification to earnings	0	0
Balance at end of period	41	65
Other
Accumulated Other Comprehensive Income Loss Net Of Tax [Roll Forward]
Balance at beginning of period	8	-8
Changes in fair value	0	16
Reclassification to earnings	0	0
Balance at end of period	8	8
Deferred tax
Accumulated Other Comprehensive Income Loss Net Of Tax [Roll Forward]
Balance at beginning of period	2	74
Changes in fair value	454	0
Reclassification to earnings	-21	-72
Balance at end of period	435	2
Accumulated other comprehensive income (loss)
Accumulated Other Comprehensive Income Loss Net Of Tax [Roll Forward]
Balance at beginning of period	-3	-119
Changes in fair value	-771	-5
Reclassification to earnings	36	121
Balance at end of period	($738)	($3)

Accumulated_Other_Comprehensiv2

Accumulated Other Comprehensive Income (Loss) - Reclassification out of Accumulated Other Comprehensive Income (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Reclassification Out of Accumulated Other Comprehensive Income [Line Items]
Fuel and oil	($5,293)	($5,763)	($6,120)
Less: Tax Expense	680	455	264
Reclassification out of Accumulated Other Comprehensive Income
Reclassification Out of Accumulated Other Comprehensive Income [Line Items]
Net of Tax	36
Fuel derivatives | Reclassification out of Accumulated Other Comprehensive Income
Reclassification Out of Accumulated Other Comprehensive Income [Line Items]
Fuel and oil	34
Less: Tax Expense	12
Net of Tax	22
Interest rate derivatives | Reclassification out of Accumulated Other Comprehensive Income
Reclassification Out of Accumulated Other Comprehensive Income [Line Items]
Interest Expense	23
Less: Tax Expense	9
Net of Tax	$14

Employee_Retirement_Plans_Deta

Employee Retirement Plans (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Defined contribution plans [Abstract]
Company contributions to all defined contribution plans expensed	$644		$497		$370
Maximum age after retirement that employees may use accrued unused sick time to pay for medical and dental premiums	65 years
Change in benefit obligation [Roll Forward]
APBO at beginning of period	138		148
Service cost	10		30		20
Interest cost	7		4		4
Benefits paid	-4		-3
Actuarial gain	21		-41
Settlements	-3		0
APBO at end of period	169		138		148
Effect of a one percentage point change in assumed health care cost trend rates [Abstract]
Increase in total service and interest costs	3
Increase in the APBO	24
Decrease in total service and interest costs	-2
Decrease in the APBO	-20
Estimated future benefit payments time period [Abstract]
2015	5
2016	6
2017	7
2018	7
2019	8
Next five years thereafter	55
Reconciliation of funded status to accrued postretirement benefit cost recognized on the balance sheet [Abstract]
Funded status	-169		-138
Unrecognized net actuarial gain	-53		-80
Unrecognized prior service cost	12		15
Accumulated other comprehensive income	41		65
Cost recognized on Consolidated Balance Sheet	-169		-138
Components of periodic postretirement benefit cost [Abstract]
Service cost	10		30		20
Interest cost	7		4		4
Amortization of prior service cost	3		3		0
Recognized actuarial gain	-4		-4		-5
Settlements	-1		0		0
Net periodic postretirement benefit cost	$15		$33		$19
Actuarial assumptions used to account for postretirement benefit plans [Abstract]
Weighted-average discount rate (in hundredths)	4.10%		5.05%		2.90%
Assumed healthcare cost trend rates [Abstract]
Assumed healthcare cost trend rate decline (in hundredths)	5.00%
Assumed healthcare cost trend rate	6.88%	[1]	7.50%	[1]	8.00%	[1]
Year the health care cost trend reaches ultimate rate (year)	2025
[1]	The assumed healthcare cost trend rate is assumed to remain at 6.88% for 2015, then decline gradually to 5.00% by 2025 and remain level thereafter.

Income_Taxes_Detail

Income Taxes (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
DEFERRED TAX LIABILITIES:
Accelerated depreciation	$4,277	$4,069
Fuel derivative instruments	0	36
Other	51	84
Total deferred tax liabilities	4,328	4,189
DEFERRED TAX ASSETS:
Fuel derivative instruments	521	8
Deferred gains from sale and leaseback of aircraft	20	24
Capital and operating leases	125	163
Deferred tax assets construction obligation	209	168
Accrued engine maintenance	83	90
Accrued employee benefits	334	307
State taxes	65	74
Business partner income	90	457
Net operating losses and credit carryforwards	3	14
Other	96	118
Total deferred tax assets	1,546	1,423
Net deferred tax liability	2,782	2,766
CURRENT:
Federal	203	355	-45
State	29	44	12
Total current	232	399	-33
DEFERRED:
Federal	421	62	287
State	27	-6	10
Total deferred	448	56	297
Total	680	455	264
Income Tax Expense (Benefit), Continuing Operations, Income Tax Reconciliation [Abstract]
Tax at statutory U.S. tax rates	636	423	240
Nondeductible items	9	10	10
State income taxes, net of federal benefit	37	25	14
Other, net	-2	-3	0
Unrecognized Tax Benefits	$5

Quarterly_Financial_Data_Detai

Quarterly Financial Data (Details) (USD $)	3 Months Ended									12 Months Ended
In Millions, except Per Share data, unless otherwise specified	Dec. 31, 2014		Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Quarterly Financial Data [Abstract]
Revenues	$4,628	[1]	$4,800	$5,011	$4,166	$4,428	$4,545	$4,643	$4,084	$18,605	$17,699	$17,088
Operating income	621		614	775	215	386	390	433	70	2,225	1,278	623
Income (loss) before income taxes	302		525	746	244	334	419	363	94	1,816	1,209	685
Net income (loss)	$190		$329	$465	$152	$212	$259	$224	$59	$1,136	$754	$421
Basic (in dollars per share)	$0.28	[1]	$0.48	$0.67	$0.22	$0.30	$0.37	$0.31	$0.08	$1.65	$1.06	$0.56
Diluted (in dollars per share)	$0.28	[1]	$0.48	$0.67	$0.22	$0.30	$0.37	$0.31	$0.08	$1.64	$1.05	$0.56
[1]	Includes a change in estimate, recorded on a prospective basis, effective October 1, 2014, which increased Passenger revenues by approximately $55 million and increased both Basic and Diluted net income per share by $.04. See Note 1 for further detail.

Airtran_Acquisition_and_Relate

Airtran Acquisition and Related Matters (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Business Combinations [Abstract]
Acquisition and integration	$126	$86	$183